Ingegnerizzazione della memoria storica ed esplorazione interattiva di documenti d'archivio: L'applicativo online per il privilegio di papa Gregorio X per la comunità monastica del Monte Sinai (1274) come prototipo
10.6092/issn.2532-8816/12567
Questo articolo presenta i risultati di un progetto di ricerca in Umanistica Digitale che esplora documenti d'archivio all'interno del sistema online Engineering Historical Memory (EHM) consentendo agli utenti di leggere fonti storiche primarie secondo diversi livelli di conoscenza e competenza in modo interattivo. Qui, come caso di studio, gli autori presentano la ricerca interdisciplinare (diplomatica, storia, animazione) che ha consentito la pubblicazione online dell’originale del privilegio concesso da papa Gregorio X alla comunità monastica del Monte Sinai nel 1274. L'applicativo comprende i seguenti strumenti di ricerca: 1) ricomposizione digitale e restauro della campagna fotografico sulla pergamena originale che è conservata in due parti in due diverse località egiziane (Sacro Monastero di Santa Caterina al Monte Sinai e Archivio dello stesso monastero al Cairo); 2) force-directed graph per navigare la struttura diplomatica del privilegio papale; 3) visualizzazione geospaziale interattiva dei toponimi (viste satellitari e mappe politiche); 4) motori di ricerca accademici per testi, immagini e video relativi alle singole entità diplomatiche, storiche e geografiche identificate nell’applicativo; 5) modellazione 3D del perduto sigillo pendente in piombo del privilegio; 6) sistema sviluppato ad hoc per la visualizzazione sul web del modello 3D del sigillo.
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Engineering Historical Memory and the Interactive Exploration of Archival Documents: The Online Application for Pope Gregory X’s Privilege for the Monastic Community of Mount Sinai (1274) as a Prototype
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Engineering Historical Memory and the Interactive Exploration of Archival Documents: The Online Application for Pope Gregory X’s Privilege for the Monastic Community of Mount Sinai (1274) as a Prototype
https://umanisticadigitale.unibo.it/article/view/12567/13099
   Umanistica Digitale – ISSN: 2532-8816 – n. 10, 2021
A. Nanetti, D. Benvenuti – Engineering Historical Memory and the Interactive Exploration of
Archival Documents
DOI: http://doi.org/10.6092/issn.2532-8816/12567



     Engineering Historical Memory and the Interactive
Exploration of Archival Documents: The Online Application
for Pope Gregory X’s Privilege for the Monastic Community
           of Mount Sinai (1274) as a Prototype

                                 1
                                  Andrea Nanetti, 2Davide Benvenuti

                             Nanyang Technological University, Singapore
                           1,2

                                     1andrea.nanetti@ntu.edu.sg
                                       2dbenvenuti@ntu.edu.sg




       Abstract

This paper presents the results of a research project in Digital Humanities. The project explores
archival documents within the online system Engineering Historical Memory (EHM). EHM
enables users to read primary historical sources according to different knowledge and expertise
levels interactively. Here, as a showcase, the authors present the interdisciplinary research
(Diplomatics, History, 3D Visualisation) that empowered the online publication of the original
privilege issued by pope Gregory X to the monastic community of Mount Sinai in 1274. The
application embodies the following research tools: 1) Digital recomposition and restoration of
the photographic survey of the original parchment split into two pieces and held in two different
locations in Egypt (Holy Monastery of St Catherine at Mt Sinai, and the Archive of the same
monastery in Cairo); 2) Force-directed graph to navigate the diplomatics structure of the papal
privilege; 3) Interactive geospatial visualisations of the place names (satellite views and political
maps); 4) Search engines for scholarly texts, images, and videos related to the individual
diplomatics, historical, and geographical entities itemised in the application; 5) 3D modelling of
the lost lead seal of the privilege; 6) Customary web-based visualisation tool for the 3D model of
the seal.
Questo articolo presenta i risultati di un progetto di ricerca in Umanistica Digitale che esplora
documenti d'archivio all'interno del sistema online Engineering Historical Memory (EHM)
consentendo agli utenti di leggere fonti storiche primarie secondo diversi livelli di conoscenza e
competenza in modo interattivo. Qui, come caso di studio, gli autori presentano la ricerca
interdisciplinare (diplomatica, storia, visualizzazione 3D) che ha consentito la pubblicazione
online dell’originale del privilegio concesso da papa Gregorio X alla comunità monastica del
Monte Sinai nel 1274. L'applicativo comprende i seguenti strumenti di ricerca: 1)

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ricomposizione digitale e restauro della campagna fotografico sulla pergamena originale che è
conservata in due parti in due diverse località egiziane (Sacro Monastero di Santa Caterina al
Monte Sinai e Archivio dello stesso monastero al Cairo); 2) force-directed graph per navigare la
struttura diplomatica del privilegio papale; 3) visualizzazione geospaziale interattiva dei toponimi
(viste satellitari e mappe politiche); 4) motori di ricerca accademici per testi, immagini e video
relativi alle singole entità diplomatiche, storiche e geografiche identificate nell’applicativo; 5)
modellazione 3D del perduto sigillo pendente in piombo del privilegio; 6) sistema sviluppato ad
hoc per la visualizzazione sul web del modello 3D del sigillo.



       Introduction

In recent years, the influence of visual imagery has advanced, and new tools and techniques have
been increasingly exploited to the benefit of interdisciplinary research ([21]). Information
visualisation has become an essential and meaningful approach for digital history to explore
complex data sets ([9]: 5). It can be construed as a powerful guide for exploring primary historical
information and generating new research opportunities to search in online secondary literature
repositories ([11]). Nowadays, several visualisation solutions can be tested and successfully used
by historians in their perennial chase for truth ([26]). Therefore, good information visualisation
can help enlighten the relations among different historical information ([16]) to promote the
sharing and participatory interpretation of historical memory.
Since 2007, Engineering Historical Memory (EHM) is an ongoing research project that
welcomes international and multidisciplinary collaboration to design and test interactive
applications for the virtual (re)organisation and delivery of historical knowledge in the digital
age. The EHM research team studies and practises "by what means" traditional historical
scholarship can supply machine-readable information. The aim is to empower historical sciences
with artificial intelligence and machine learning, thus enabling all users to read primary historical
sources according to different knowledge and expertise levels interactively. In the history domain,
EHM makes a cross-disciplinary use of established research processes, such as mapping as
understood in mathematics and linguistics (i.e., an operation that associates each element of a
given set, the domain, with one or more items of a second set, the range) and parsing as
understood in computing (i.e., analyse narratives into logical syntactic components) to kick-off
the exploration of primary historical sources. Using these operations of mapping and parsing for
individual primary historical sources, EHM associates each element of given sets of information
provided by the domain of the traditional disciplines (e.g., history, art history, philology,
palaeography, diplomatics, codicology, archaeology, epigraphy, sigillography) with one or more
elements of the range of machine-readable content management systems (e.g., spreadsheets,
computational notebooks).
The level of accuracy of this preliminary human activity is directly proportional to that of the
aggregations generated and visualised by the EHM algorithms from different sets of similar
written or depicted elements in the EHM database (e.g., geographical names, people’s names,
goods, ships, governments, events, architectures, drawings) and potentially relevant publications,
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images, and videos retrieved in online repositories. To understand and emphasise the unity of
EHM as an interactive system in the approach to historical information, the rhetorical and
conceptual linking of “mapping and visualisation” as well as “search and visualisation” should be
hendiadys. Thus, in its primary meaning, the term “mapping” is understood as the localisation
and description of elements, facts or phenomena that relate to a circumscribed area, historically
understood at the intersection of precise space and time coordinates. The aim is to provide and
test an example of an innovative epistemological process to distil historical data visually. The
“visualisation” process is seen not as a reductive representation to epitomise and/or illustrate
written narratives but as an investigative tool that the historian (especially one who intends to
enter fully into the digital era) can use for discovering and organising new relationships between
objects, in a new historical landscape where past, present, and future can merge in a democratised
whole. Refer to [2] and [8].
On EHM, five main types of information visualisation have been experienced as participatory
opportunities for digital history. The application approached some best practices related to
Radial Tree, Treemapping, Force-Directed Graph, OpenStreetMap and Satellite View in digital
history to initiate a discussion. This exercise generated an information visualisation application
that enables scholars to submit website reviews using an online template ([25]).
In this research context, the archival document has its peculiarity and needs to be investigated
using the methods of three major academic disciplines: palaeography, diplomatics, and history.
Usually, in academic literature, these disciplines explore and study the documents in research
silos. This application can be construed as an answer to the critical question addressed and
discussed in the webinar organised by the Laboratorio di Cultura Digitale and EHM on 22 and
23 June 2020. This consideration is because this EHM application establishes a landmark in
unifying the three multidisciplinary approaches to archival documents and providing a “digital
humanities” interdisciplinary experience to the user. Refer to Figure 1. Identifying an alternative
method for the digital processing of information embedded in archival documents relies upon
the demonstration that archival documents are highly structured, and traditional disciplines can
teach digital technologies how to decode the content and transfer it into a machine-readable and
machine-understandable format. This process also addresses the second key question of the
webinar, which was about creating digital editions of historical sources that do not respond to a
single category of users, usually coinciding with that from which the edition itself originates.
This EHM application shows how making information machine-understandable allows digital
systems to satisfy different audiences simultaneously and the various queries that come from
individual audiences under different circumstances.
The paper is structured in six sections (excluding this introduction). Section 1 presents the digital
recomposition and restoration of the photographic survey of the original parchment, which is
split into two pieces and held in two different locations in Egypt (Holy Monastery of St
Catherine at Mt Sinai and the Archive of the same monastery in Cairo). Section 2 introduces the
force-directed graph to navigate the diplomatics structure of the papal privilege. Section 3
illustrates the functions and operability of the interactive geospatial visualisations used for place
names (satellite views and political maps). Section 4 describes the search engines for scholarly

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texts, images, and videos related to the individual diplomatics, historical, and geographical
entities itemised in the application. Section 5 showcases the 3D modelling of the lost lead seal of
the privilege. Section 6 explains the development and implementation of the customary web-
based visualisation tool for the 3D model of the seal. The paper ends with the acknowledgement
of research collaborations and bibliographical references.




Figure 1: Screenshot from EHM. URL
https://engineeringhistoricalmemory.com/MountSinai.php?vis=sat



        1. Digital recomposition and restoration of the original
        parchment’s photographic documentation 1

The original artefact is presently divided into two pieces: ink on parchment (ca 57x68cm), Ιερά
Μονή Θεοβαδίστου Όρους Σινά, Αγίας Αικατερίνης/Holy Monastery of St Catherine


1   In this section, subsections 1.1, 1.2, and 1.3 are based on the report submitted by Andree Hanse
    Wibowo, who was tasked by Andrea Nanetti to digitally reconstruct a composite image of the
    document with the aid of an image editing software under the supervision of Davide Benvenuti. The
    steps detailed in this report can be construed as the most accurate and convincing image composite of
    the 1274 document based on the available photographs. While not perfect, this reconstruction has
    done justice at creating a reliable digital documentation of the original document for any future
    analysis and study of this Gregory X’s privilege, until a new digital photographic campaign is done.
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(Egypt), right part (ca 28.5x68cm) in the cabinet of the Archive of the monastery at Mount
Sinai, left part (ca 28.5x68cm) in the strongbox of the Archive of the monastery in the Metochion
(dependency) at Cairo. The overall state of preservation can be described as fair since the
readability has not been affected, even if the supporting script has suffered minor mutilations
that correspond to the intersections of the folds, three horizontal and three vertical ones, and is
now bereft of the lead seal suspended from a silken thread. On both the front and the back, there
are chancellery notes that document its archival life 2.
The digital reconstruction is based on the image information provided by the digitalisation of
27 analogue photographs capturing various sections of the 1274 privilege issued by Pope Gregory
X for the monastic community of Mount Sinai 3. When described as a different version, it means
that the photograph could either be as follows.
     i.    The same shot but colour corrected, rotated, or digitally manipulated in any other way
           to increase the visibility of certain features of the papal bull.
     ii.   A different shot of the same section of the bull, with the same approximate angle and
           magnification.
Meanwhile, a detail or zoom shot means a closer shot or a zoomed-in crop of the same section of
the bull, focused on a specific feature or point of interest. Regarding units with multiple versions,
it is necessary to decide on one for the reconstruction process. Additionally, while the
incorporation of detail/zoom shots is prioritised as much as possible, they may still be omitted
when their image quality is equal to or lower than that of the photograph of the section. Deciding
on which photo is most suitable for the reconstruction process is an exercise in trial-and-error
and inevitably introduced some subjective artistic judgement. However, colour and image clarity
are the two most deciding factors in the elimination process. It is often the case that unedited
versions are preferable with colours as it retains more information potentially lost due to colour
correction. It is also easier to achieve a coherent overall look with unedited versions than edited
ones, which may have exaggerated unnatural colours or lighting quirks (Figure 2). How clear or
sharp some images are, is often directly determined by the image size and resolution (Figure 3).
To construct a composite image, the emphasis is put more on choosing sections that come
together seamlessly as possible. Some areas heavily edited to increase the legibility of faded texts
may not be incorporated into the composite but should still be used as a reference when trying
to transcribe or decipher the writings in question. The necessary steps are then repeated until the
final reconstruction is completed. In the following sections, each step is described in a more
detailed manner.


    Subsection 1.4 is based on the report submitted by Khoi Vu for the research assistantship supervised
    by Andrea Nanetti at Engineering Historical Memory in November 2020.
2   The first critical edition was provided in 2008 (refer to [24]; and now, the online edition with
    commentary in English [27]). The document has not yet been included in Monasterium.net.
3   The software used is Adobe Photoshop® (PS). As the document’s writing has a transverse course (i.e.,
    parallel to the parchment sheet's minor side), the image is displayed vertically.

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Figure 2: Photographed by Andrea Nanetti during a palaeographic mission of the Centre of History and
Palaeography of the National Bank of Greece Cultural Foundation (Director, Agamemnon Tselikas, 19-
24 January 1994). Digital reconstruction of the artefact by Andree Hansen Wibowo (May 2020).
Copyright of the Holy Monastery of St. Catherine at Mount Sinai. The images of the papal bull have
been first published with permission (Rev. Father Symeon, Librarian of the Monastery of St Catherine,
and Agamemnon Tselikas, January 2001) as Tables 3-4 and 7-8 (right part) and Tables 1-2 and 5-6 (left
part) in Nanetti, 2008. The images on the left show four of the original exaggerated shadows. The edited
version’s intense blue tinges on the right present a challenge in creating a coherent image composite.




Figure 3: This is an example of decisions that had to be taken in the digital reconstruction. Although the
detail below has a higher resolution and pixel size, it is apparent that the image above has an inherent
greater clarity and would therefore be a more fitt fitting photograph to be used for the image composite.

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These images were used by Antonella Ghersetti and Frédéric Bauden for the transcription, transliteration,
and translation of the archival information in Arabic (refer to [27]).

        1.1. Insert Photograph as Smart Object
This reconstruction leverages the Non-Destructive Editing (NDE) using Smart Object workflow
available using Photoshop (PS from now on). This workflow allows retaining memory of an
image's original state regardless of the number of edits applied to it.
         1.1.1. Match Lighting and Colour
Figure 1 shows that the lighting of the papal bull sections is varied and uneven, so the best
solution is to first adjust the segments' brightness to a commonly accepted standard. The
photographs' non-standardised nature required multiple adjustment layers to achieve a unified
look across all the different sections. In this adjustment` process, Levels are an advanced version
of Brightness/Contrast. It factors in the image’s brightest highlights and darkest shadows instead
of applying a sweeping brightening or darkening image. Curves is an even more fine-tuned
version of Levels and has the added feature of allowing users to sample an image to copy its
colour tone, which significantly aids the matching process. A clipping mask was set onto each
adjustment layer to ensure that each adjustment layer only affects its targeted photographic
segment.
          1.1.2. Align Photographic Segments
Evaluating the photographed sections shows that adjacent segments overlap and present the same
image information on the papal bull's specific areas. Theoretically, this makes it possible to
position adjacent pieces and adjust them with each other until the overlapping areas align
perfectly. However, perfect alignment is impossible due to the variance in the original
photographs' lighting condition and lens magnification. Furthermore, the papal bull's physical
condition did not provide consistent shapes across the different photographic sections. This
characteristic makes the blending mode a helpful tool to indicate the degree of alignment
between two photographic segments. If aligned well, we should see a strip of black where the two
pieces overlap. Otherwise, we will see false colours where the two image layers misalign. This is
also why the previous step standardises the lighting. A difference in the image brightness would
be registered as a difference in colour under the Difference layer blending mode. Thus, with this
Difference blend mode on, the next step was manipulating the scale, position and rotation of the
photographic sections as needed, using each other as a marching guide. Refer to Figure 4 for an
example.




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Figure 4: An example of a well-aligned section (Top) compared to a misaligned one (Below) under a
'Difference' blending mode.
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The photographic segment’s position, scale, and rotation were manipulated. Once the
overlapping areas are satisfactorily aligned, the changes can be confirmed, and the layer blending
mode can be turned back to Normal. This process restores the photographic segments’ true
colours in overlapping areas.
          1.1.3. Create a Seamless Transition
After the photographic segments are adequately aligned, there may still be traces of misalignment
or change in image brightness, manifesting as a break between the two elements. The subsequent
creation of a Layer Mask allowed a smooth transition between the two segments. Layer Mask
and masking allows to effectively ‘erase’ certain parts of a photographic segment’s edge while still
retaining the image information if it should be needed back in line with the Non-Destructive
Editing principles. Finally, masking the image with a soft-edged brush integrates the two image
segments with a gradual transition between slightly different brightness or lighting conditions.

       1.2. Global Adjustments
Applying the previously outlined procedures to reconstruct both the recto (Figure 5) and the
verso (Figure 6) of the papal bull, a relatively complete image composite of the provided
photographs was obtained.




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Figure 5: Recto (front side) of the 1274 Papal Bull issued by Pope Gregory X, work-in-progress.




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                                                                          Archival Documents




Figure 6: Verso (backside) of the 1274 Papal Bull issued by Pope Gregory X, work-in-progress.


As shown in Figure 5 and Figure 6, although the primary form of the papal bull could be restored,
still some imperfections are visible and compromise the appreciation of the content. Therefore,
global adjustments would be required to tackle these imperfections, meaning that the edits
performed in this stage are intended to affect the photographic segments. Instead of aligning two


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or three pieces together, the adjustment aims to improve cohesiveness and coherence across all
the photographic elements. The two main issues tackled in this stage are the following.
     i.        Correct Alignment of Textual Information.
     ii.       Extrapolation of Missing Paper Edges.
         1.2.1. Correct Alignment of Textual Information
On the recto of the papal bull, a closer look at the image composite reveals that the textual
information is not lining up correctly in certain areas due to the letter's creasing and tearing.
Figure 7 and Figure 8 provide two significant examples.




Figure 7: Example of how creasing causes some text to be misaligned.




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                                                                          Archival Documents




Figure 8: Example of how tears cause some text to be misaligned.


The correction of this imperfection requires selectively distorting parts of the image composite,
which could be done in a few steps.
     i.    The first step was to determine how much of the image composite should be distorted.
           This was done by considering the number of lines that are incorrectly aligned and the
           nature of the tear.
     ii.   A selection will then be made of this part of the image composite. This selection will
           create both a layer mask and a duplicate of that area of the letter. See Figure 9 for an
           explanatory diagram.
     iii. The duplicated section is then made into a Smart Object to retain its original image
          quality before being distorted and warped to align with the letter's remaining areas.
     iv. Creating a seamless transition between the duplicated section and the remaining
         sections after aligning them is done using the same method described in Step 4 of the
         Image Reconstruction Process.
This process is repeated for all the misaligned textual information in the recto image composite
until they are corrected.




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                                                                          Archival Documents

Figure 9: (A) Area of the letter where selection is made is shown in red. (B) Layer Mask created using the
section in (A). (C) Selection in (A) duplicated as a new image layer.


          1.2.2. Extrapolation of Missing Paper Edges
Due to the photographs' framing, some document edges were not captured in the photographic
sections. This lack of image information results in the image composite as abrupt hard edges
(Figure 10).




Figure 10: Highlighted in cyan are examples of the straight edges on the recto (left) and the verso (right)
because of missing photographic information in the photographic documentation.


When mirrored, the verso can add image information to the recto's edges and vice versa. Rather
fortuitously, where the edge is missing on one side, it is present in the other, and as such, this
extra information is enough to extrapolate how the missing edges might have looked like. The
following steps would describe the extrapolation process using the verso as an example. The first
step was to bring in the recto as a Smart Object layer and reflect it horizontally. The recto would
then be transformed and distorted to fit the shape of the verso best, as shown in Figure 11.




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Figure 11: The mirrored recto, distorted to fit the form of the verso best and placed as a layer behind it.


A new layer was then created. The layer was masked to the shape of the mirrored recto and then
used to recreate the verso's colour and texture using a combination of Stamp Tool and Spot
Healing Brush Tool. While the Stamp Tool copies the sampled part of the image onto wherever
the user chooses to apply it, the Spot Healing Brush Tool uses a process known as Content-
Aware Sampling that automatically generates image information to blend away perceived
anomalies based on the software’s analysis of the image.

        1.3. Result of the digital reconstruction
Figure 12 and Figure 13 show the digital recomposition and restoration of the original
parchment’s photographic documentation.




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Figure 12: Recto of the 1274 Papal Bull issued by Pope Gregory X, result.




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Figure 13: Verso of the Papal Bull issued by Pope Gregory X, result.



        1.4. Result of the digital reconstruction
The web experience optimisation has been achieved through three meaningfully consequential
actions: split, highlight, store.



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          1.4.1. Split
To provide easy and fast browsing of high-resolution images on webspace, EHM uses Zoomify,
which is both a format and a tool for deep zooming into high-resolution images. The tool resizes
high-quality image into different lower resolution images, then splits them into smaller pieces
with a fixed size of 256×256, which can be loaded partially corresponding to how users interact
with the map. For example, the digitally reconstructed image of pope Gregory X’s parchment
has 3876×4335 pixels and is split as follows.
Layer 0: Width 387625121, Height 433525135 => 1 piece (121x135)
Layer 1: Image resized: Width 387624242, Height 433525270 ⇒ 2 pieces (one piece 242×256
and another piece 242x14)
Layer 2: Image resized: Width = 387623484, Height = 433523541 ⇒ 6 pieces (2 pieces
256×256, one piece 256x29, 2 pieces 228x256, 1 piece 228x29)
Layer 3: Image resized: Width = 387622=969, Height = 4335221083 ⇒ 20 pieces
Layer 4: Image resized: Width = 387621=1938, Height = 4335212167 ⇒ 72 pieces
Layer 5: Image resized: Width = 387620=3876, Height = 4335214335 ⇒ 272 pieces
This format allows a smooth, easy loading of the zooming level selected by the user. At the same
time, it safeguards the copyright of the high definition original image, which is not available.
          1.4.2. Highlight
This action aims to collect the “coordinates” of all items that the user can select on the original
document and activate specific EHM tools and searches. The “coordinates” are a list of numbers
that describe the points set on the digital document to identify the perimeter of individual items.
The value of the numbers depends on the resolution of the image. A pair of two adjacent numbers
constitute the abscissa and ordinate of the point. After that, the coordinates are transferred into
a dedicated column of the Google Spreadsheet. The other information about the item is also
saved (e.g., ID, title, commentary, English translation, etc.).
        1.4.3. Store
The image pieces split by Zoomify are then stored on Microsoft Azure virtual machine (Linux).

       2. Force-directed graph to navigate the diplomatics structure of the papal
privilege4
The tenor formularis (i.e., the diplomatic organisation) constitutes the juridical structure of the
archival document. It is essential for the historical reading of the document. This methodology
is rooted in the diplomatics teaching imparted by Paolo Selmi at the School of Palaeography,
Archival Studies, and Diplomatics of the Archivio di Stato di Venezia. However, most historians

4   This section is based on Andrea Nanetti’s work ([24];[27]). The force-directed graph has been
      developed by Khoi Vu under Andrea Nanetti’s supervision and is now accessible online interactively
      ([27]).
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seem not to consider its importance because they lack diplomatics training. As a result, the
historical information extracted from archival records does not clearly distinguish between
standard formulas, common to all similar documents, and the formulas, which are peculiar to
the specific iuris actus of the document.
On the other hand, the palaeographer and the diplomatist don’t find it easy to retrieve the
necessary historical contextualising information to read the iuris actus with other relevant
documentation critically. Therefore, the EHM research team explored different visualisation
methods to provide the historian with a clear and straightforward explanation of the tenor
formularis and the palaeographer and diplomatist the relevant historical contextualisation. This
double and complementary understanding of the primary source is now on the same page, and
different disciplinary approaches can interact and discuss together.
The choice was to use a force-directed graph drawing algorithm to provide a clear and
straightforward understanding of the tenor formularis. The force-directed graph is a class of
algorithms for drawing diagrams in an aesthetically friendly way as well. The purpose of these
algorithms is to position the nodes of a graph in two-dimensional or three-dimensional space so
that all the edges are of equal length. There are as few crossing edges as possible by assigning
forces among the set of edges and the set of nodes, based on their relative positions, and then
using these forces to simulate the motion of the edges and nodes or minimize their energy.




Figure 14: Screenshot of the interactive force-directed graph to navigate the papal privilege's tenor
formularis (diplomatic structure).


The force-direct graph has been used here to visualise the methodology for the analysis of the
tenor formularis (diplomatic structure) of a papal document that was taught to Andrea Nanetti
by Paolo Selmi in the School of Palaeography, Archival Studies, and Diplomatics at the Archivio

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                                                                          Archival Documents

di Stato di Venezia in 1991-1992 (refer to [24] and [27]). In the analysis of the tenor formularis,
what arises continually is the similitudes with the privilege of Celestine III in favour of the
Canonica Portuense of Ravenna dated 20 May 1196. This privilege renewed word for word the
preceding ones of Innocent II, 1130-1143, and of Adrian IV, 1154-1159 (refer to Ravenna,
Archivio di Stato, Tabulario Portuensi, Capsa C. Num. 671, published in [15]: 167-170, no.
LXXXVII). This fact proves that the privilege for Mount Sinai uses the standard formulary put
in place by the Holy See for privileges granted to monastic communities. A brief description of
the tenor formularis is provided in the next subchapters. For a full appreciation of the document,
refer to [24], Italian, and [27] in English.

       2.1. Protocollum
The protocol (protocollum, r. 1) opens with the intitulatio. The pope nominates himself without
the ordinal number with the title of ‘episcopus’ and the formula ‘servus servorum Dei’, as usual in
documents containing privileges. There follows in the dative case the inscriptio ‘venerabili fratri
episcopo et dilectis filiis fratribus Montis Synay …regularem vitam professis’. “The papal letter
regularem vitam eligentibus is not found in the old book of the papal chancellery, namely in the
Liber diurnus, but in that of the first half of the thirteenth century as a typical expression of the
grant granted to the Cistercians. From 25 points of the Cistercian privilege, ten identical
formulae are found in Mount Sinai's privilege. At the same time, a further two are taken from
the kind of papal privileges beginning with the words “In eminenti Apostolicae Sedis specula”.
Refer to [19]: 286. The words “regularem vitam professis” also constitute the closure of the
inscriptio in the above-mentioned privilege of Celestine III in favour of the Canonica Portuense
dated 1196. Refer to [15]: 167-170). The usual honorary appellations used for bishops are
observable (venerabilis frater) and for all the persons in general (dilectus filius), where the emperor
and king had the address charissimus in Christo filius and ladies had dilecta in Christo filia (refer
to [17]: 40). The protocol closes with the formula of perpetuity ‘in perpetuum’, which during
this period substituted the salutation when the grant was accomplished, as is the case here,
without limitations of time and place.

       2.2. Mesocollum
In the text (or mesocollum), after the arenga (r. 2), which proceeds from the ‘religiosam vitam’ to
‘infringat’, there is a long multiple iuris actus, from ‘Eapropter’ (r. 2) to ‘salva Sedis Apostolice
auctoritate’ (r. 29), in which the juridical act is expressed in the following arranged clauses.

       2.3. Escatocollum
The closing section of the document (known as escatocollum, refer to [30]: 33-81) commences
with the pope’s subscription, articulated in three separate elements arranged on the same line (r.
33, refer to [17]: 21-22).




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3. Interactive geospatial visualisations of the place names (satellite views and political maps) 5
The online application for pope Gregory X’s privilege for the community of Mount Sinai (1274)
used satellite view and OpenStreetMap. Satellite view provides image data obtained by
photographing or scanning earth or other planets by various artificial earth satellites. It allows
the contextualisation of historical-geographical data into the physical world. See an example in
Figure 15. OpenStreetMap is an online mapping collaborative effort that provides user-generated
street maps that can be free editable ([33]). It allows the contextualisation of historical-
geographical data into the present political situation. See an example in Figure 15. The
combination of these two tools provided a wealth of geographic data and spatial analysis.




Figure 15: Screenshots of selected properties of the monastery in Cairo and Jerusalem show the
connection between the document and the geospatial visualisation tools (satellite view for Cairo and
OpenStreetMap for Jerusalem).


5
    This section is based on the report submitted by Liu DanYun for Liu, DY., Nanetti, A., Vu, N. K.
    (Eds.). EHM – Information Visualisation for Digital History. Retrieved from
    https://engineeringhistoricalmemory.com/Visualisation.php (accessed on 2021-2-11).

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                                                                          Archival Documents

           4. Search engines for scholarly texts, images, and videos related
           to the individual diplomatics, historical, and geographical
           entities itemised in the application 6

EHM has developed search algorithms to aggregate knowledge (Figure 16). Each item is
identified using a relevant Wikipedia page whenever available. Based on this identification, EHM
picks keywords and filters to aggregate knowledge from leading online repositories about any
item selected by the user in the online application in real-time. Some of the resources are searched
through their API (application programming interface), which is either public (e.g., Europeana,
Gallica, YouTube, Vimeo, Google Images, Bing Images) or shared upon research collaboration
agreement (e.g., Taylor & Francis, Scopus-Elsevier). Other online repositories do not have the
policy to share their APIs for federated searches publicly. In these cases, the user is prompted to
link to the official websites one by one in separate tabs; an automated query consistent with the
selected item is automatically filled to facilitate the search. Online repositories without API are
not included in the EHM search (e.g., SmartHistory). In EHM, the search results are visualised
under four categories as follows.
     i.     Scholarly publications from Europeana, Gallica, Taylor & Francis, Scopus-Elsevier, via
            API.
     ii.    Images from Google Images, Bing Images, via API.
     iii. Videos from YouTube, Vimeo, I Media Cities, via API.
     iv. Guided search in other relevant resources that do not share their API publicly (e.g.,
         GettyImages, Google Scholar, JSTOR, China National Knowledge Infrastructure,
         Wanfang Data, Pelagios, Blackwell)
With most of the resources, search APIs work by looking for input keywords in the digital
documents accessible online (title, author, abstract, full text). Taylor & Francis also provides a
cutting-edge service, which allows searching by “concept”. This means that the algorithm also
searches the Taylor and Francis databases for concepts related to the set keywords.




6
    This section is based on the report submitted by Khoi Vu for the research assistantship supervised by
    Andrea Nanetti at Engineering Historical Memory in November 2020.

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Figure 16: Screenshots of EHM Search Engines for scholarly texts (b, d, f), images (a), and videos (c)
related to the individual diplomatics, historical, and geographical entities itemised in the online
application for pope Gregory X’s privilege for the monastic community of Mount Sinai (1274). The
identifier of the item is the corresponding Wikipedia page (e).


Within EHM, the user can explore the digital images of primary historical sources and their
critical editions and stay tuned with relevant secondary literature interactively and in real-time.
These are two EHM essential innovations to approach the online publication of primary
historical sources. In EHM, information is organised into two main streams: texts and images.
In the case of Gregory X’s document, the process started with the text of Andrea Nanetti’s critical
edition and commentaries (history and diplomatics; refer to [24]), whose information was
transferred into a machine-readable format using Google Spreadsheet as a content management
system and data storage solution because of several concurrent advantages: powerful, popular,
secure, robust, customizable, easy backup, and, finally, the similarity with MySQL database in
table-like construction. A diagram in Figure 17 illustrates the EHM workflow.




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    A. Nanetti, D. Benvenuti – Engineering Historical Memory and the Interactive Exploration of
                                                                          Archival Documents




Figure 17: Workflow of the EHM search drawn by Khoi Vu.



       5. Digital process for the 3D modelling of the lost lead seal of
       the privilege 7

The parchment used as writing support, quite often, and above all whitened only on the part on
which the text is placed, as is customary in bulls, allows one, together with the other usual
intrinsic and extrinsic characters, to recognise the document as a solemn privilege and to suppose
the presence of a lost leaden seal cum filo serico (with a silken cord, Figure 19), or rather cum
serico, meaning by sericum a silken cord, consisting of numerous single threads partly red and
partly yellow (for the litterae cum serico refer to [18]: 57-71, with footnote 9 at 57-58; for
pontifical sigillography, refer to [31]; [4]; [20]). The bullatores, often illiterate, assigned a cord

7
    This section is based on [24], [27], and on the the report submitted by Yap Wei Wen Marc for the
    student work supervised by Davide Benvenuti.
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of silk or hemp to a document based on the initial letter of the pope’s name: if cum spatiis et
floribus erat (it was with spaces and flowers), they used to assign a silken cord, and if impleta
incausto (full of ink) then one of hemp (cum filo canapis; refer to [24]). Furthermore, the
parchment shows the usual folds before the plica (i.e., surrounding cover) of the lower margin,
where the two holes through which the sericum sealed with the lead must pass are still discernible.
Papal bullae acted as seals on official papal documents to authenticate their provenance and
authority. On the bulls with leaden seals of Pope Gregory X still extant, we see two faces
following the model fixed under Paschal II (1099-1118) and remaining unchanged after that
(refer to [17]: 49). An example of “lead alloy Papal Bulla of Gregory X (date: 1271-76; diameter
37mm, thickness 5mm, weight 39.63g, excellent condition)” is in London, British Museum. A
.jpg image is available under CC BY-SA 2.0 on the Wikipedia page of Pope Gregory X, with the
note “thanks to The Portable Antiquities Scheme/The Trustees of the British Museum, File
2593”. However, according to the British Museum Images Account Manager, “any images
available on Wikipedia are not authorised copies” (e-mail 24 June 2020). Refer to Figure 18.




Figure 18: Lead seal of Gregory X (cum filo canapis, with hemp cord). – Obverse (left image). On the
left, St. Paul is depicted with full facial features, long straight hair, and a beard. On the right, St. Peter is
also shown with complete facial features and pellets from his curly hair and beard. Above the heads, the
saints’ abbreviations are still partially visible, with ‘SPA’ for St Paul to the left and ‘SPE’ for St Peter to
the right. Both heads were separated by a tear-drop formation of linear beads, which surrounds the head
motif with a cross pattée supported on a staff between them. – Reverse. GRE/GORIVS/PP X’. The
description is based on [35]: 156, crediting Venice, Archivio di Stato, SS. Felice e Fortunato di Ammiana,
in Procuratori di S. Marco ‘de supra Canale’, n. 136) © Archivio di Stato di Venezia, Procuratori di San
Marco ‘de supra Canale’, b. 136 (Gregorius X, bulla plumbea cum filo canapis); digital images: courtesy
of Dott. Gianni Penzo Doria.




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    A. Nanetti, D. Benvenuti – Engineering Historical Memory and the Interactive Exploration of
                                                                          Archival Documents




Figure 19: Celestinus III (silk cord with colours faded by time). © Archivio di Stato di Venezia,
Procuratori di San Marco ‘de supra Canale’, b. 136 (Celestinus III, bulla plumbea cum filo serico); digital
images: courtesy of Dott. Gianni Penzo Doria.


To offer a complete reconstruction of the document, the research team decide to recreate a 3D
model of the lost lead seal and an online costumery web system to visualise the model itself on
the web, as shown in Figure 20. The work is based on different sets of 2D photographs of still
extant lead seals held in the Archivio di Stato di Venezia taken by Gianni Penzo Doria on 20 July
2020. Firstly, to ensure that the scale is as accurate as possible, the dimensions (3.7cm by 0.5cm)
of the seal were measured. A cylindrical polygon was used to block out the seal's basic shape and
critical features in Autodesk® Maya®. Once the rough mock-up was mapped out, the mesh and
geometry were later imported into the ZBrush® software for further detailing. Several problems
arose from this process, mainly the alignment and the approximation of the coin to the source
images. For example, the reference images were not orthographic in view.
Furthermore, a side-view image of the seal was not provided, causing the sculptor to rely mainly
on a singular view as reference material. To alleviate this problem, several “back and forth
rotating” or trial-and-error techniques were used to fit the mesh onto the source image to sculpt
the seal's critical landmarks accurately. Most of the work was dedicated to carving the letters
stamped on the seal. The sculpting of St Peter and St Paul's facial features was a less intricate
process while compared to the letters. In sculpting, one must keep in mind the location of the
ridges and the crease because the abbreviations themselves were not flat and had a particular
extrusion value assigned individually. The geometry was exported as an ‘FBX’ into Substance
Painter, where textures could be applied. After several colours, the generator achieved its final
‘wear and tear rustic look’, and the mesh was finally exported back into Maya for a final render,
look and showcase.


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Figure 20: Screenshots of the ZBrush® interface with the model (20a); the finished model placed in a
realistic environment to test realistic lighting render (20b); the 3D Model with the silk cord (20c); the
texture mapping (UV Mapping) (20d). The work has been done by the NTU-ADM student assistant Yap
Wei Wen Marc with the materials provided by Andrea Nanetti and under the supervision of Davide
Benvenuti.



        6. Creation of the customary web-based visualisation tool for the
        3D model of the lead seal attached to the parchment with a
        silken cord 8

Initially, the 3D model of the lead seal was uploaded onto Sketchfab™, an online platform used
by content creators to post their 3D assets and make them accessible for public viewing (refer to
[28]: 1-2; and [7]: 157). In the context of 3D rendering, three lights would have to be placed
strategically to achieve this enhanced effect. Subsequently, vignettes, ambient occlusion and

8
    This section is based on the report submitted by Xu Peisen for the student work at Engineering
    Historical Memory.
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                                                                          Archival Documents

depth of field effects were added to adjust the post-processing before publishing the model. As
far as Sketchfab™ is not open access, EHM opted to create a dedicated JavaScript code of the
model was later copied and prepared for embedment onto the EHM website.
The costumery creation of a web display platform for 3D object represents a step forward in
making the EHM platform open access as using from the shelf software has limitation regarding
the amount of data that can be uploaded and the number of visualisations that can be allowed.
One major limitation hurdle in creating a customary interface is the loading time of the object
is heavily dependent on the size of the file. The research team had to strike a compromise between
the quality of the display and the time that the user will have to wait for the object to appear.
After several tests run by the EHM research team, the loading time of the model and page took
nine seconds. Hence, more work needed to be done to optimise the window's position in the
user interface of the 3D model; for example, making the 3D model’s display as an option for the
user to toggle with or testing out a larger polycount and file size. Further troubleshooting was
necessary to test the loading time of the model. This was done by adjusting the scaling and
textures accordingly. The file was later converted into the Graphics Language Transmission
Format or ‘gITF’ as a recommended workflow by the developers at ‘three.js’.



       Conclusions

In conclusion, this EHM application pioneers and tests a new set of methods to explore the
complexity of archival documents in a web environment interactively. EHM is free and open
access. Within EHM, the user can explore the digital images of the document along with their
critical editions and stay tuned with relevant secondary literature interactively. This methodology
is rooted in the diplomatics teaching imparted by Paolo Selmi at the School of Palaeography,
Archival Studies, and Diplomatics of the Archivio di Stato di Venezia. Based on this knowledge,
EHM has engaged a multidisciplinary team for diplomatics, history, digital image
reconstruction, web development, animation, and customary web-based visualisation. This
application is a scalable model for teaching and research projects in the palaeography and
diplomatics of the papal document, history of the relationship among Venice, Rome, and Mount
Sinai, and digital humanities at large.
This interdisciplinary identification of an alternative method for the digital processing of
information embedded in archival documents achieved results so far unexplored. The theory is
that technology should serve traditional disciplines and not vice-versa. In practice, as fewer
coding skills we require to the historian, the better it is. In the case of the papal bull of Gregory
X published in EHM, the juridical structure of the archival document is made available together
with the historical information in two distinct but interactively communicating datasets. The
EHM research collaborators have access to the semi-structured data from the source. Using the
Excel spreadsheet as a content management system is the sole tech skill required to the
diplomatist and the palaeographer to make their knowledge machine-readable and machine-
understandable.

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On this basis, the EHM algorithms follow up and aggregate the information visually. On EHM,
five main types of information visualisation have been experienced as participatory opportunities
for digital history. The application approached some best practices related to Radial Tree,
Treemapping, Force-Directed Graph, OpenStreetMap and Satellite View in digital history to
initiate the discussion. Thus, the historian can rely on a digital system to be aware of the juridical
structure of the archival document and clearly distinguish between repetitive formulas common
to all similar documents and the clauses, which are peculiar to the specific document under
examination. At the same time, more skilled historians have at their disposal all the tools to go
back to the original document and make an individual (re)reading of all potentially controversial
aspects. The results can be shared on the same platform and generate a discussion without
involving traditional journals that fragment and delay the advancement of learning.
Therefore, this process also addresses a second critical question about publishing historical
sources without responding only to a single category of users, usually coinciding with that from
which the edition itself originates. EHM demonstrates how making information machine-
understandable allows digital systems to satisfy different audiences simultaneously because of the
different layers of information. Furthermore, the system can be used in different settings (e.g.,
portable devices, desktop computers, large interactive screens, projection mapping) and answer
various queries from individual audiences under different circumstances. Finally, on EHM, the
historian cannot adopt a manipulative selection of information. Individual historians can build
their narrative, write their stories in a system that highlights what has been selected, neglected,
and ultimately how historical information becomes historical knowledge with given authorship.



       Acknowledgements

Andrea Nanetti has photographed the original parchment during a palaeographic mission of the
Centre of History and Palaeography of the National Bank of Greece Cultural Foundation
(Director, Agamemnon Tselikas, 19-24 January 1994). The images of the papal bull have been
first published with permission (Rev. Father Symeon, Librarian of the Monastery of St
Catherine, and Agamemnon Tselikas, January 2001) as Tables 3-4 and 7-8 (right part) and
Tables 1-2 and 5-6 (left part) in Nanetti, 2008. Further reproduction is prohibited without the
permission of the copyright owners. The first critical edition and commentary of this document
have been published by Andrea Nanetti, L’originale del privilegio Religiosam vitam di papa
Gregorio X per il Monte Sinai (1274). Edizione e commento, in Studi di storia del Cristianesimo.
Per Alba Maria Orselli, edited by Luigi Canetti, Martina Caroli, Enrico Morini, Raffaele Savigni.
Ravenna: © A. Longo Editore (Le Tessere, 16), [July] 2008, pp. 235-268, with 13 plates (pp.
209-217). The paper has been translated into English by Nicolas Coureas and Andrea Nanetti.
Nanyang Technological University Singapore has funded the translation work of Nicolas
Coureas (StartUp Grant 2014-2016, M4081357, PI Andrea Nanetti) and published with the
permission of A. Longo Editore on Engineering Historical Memory. The original parchments'
digital reconstruction was accomplished by the NTU-ADM undergraduate student Andree
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                                                                          Archival Documents

Hansen Wibowo in May 2020. The modelling of the lost lead seal of Gregory X was made by
the NTU-ADM undergraduate student Yap Wei Wen Marc in November 2020. Both students
were engaged as student training assistants supported by the Ministry of Education, Singapore,
under its Academic Research Fund Tier 1 (PI Andrea Nanetti, 2017-2020, RG55/17NS). The
modelling of the lead seal was based on images of the papal lead seals provided by the Archivio
di Stato di Venezia, Procuratori di San Marco ‘de supra Canale’, b. 136 (Gregorius X, bulla
plumbea cum filo canapis; Celestinus III, bulla plumbea cum filo serico; Innocentius III, bulla
plumbea cum filo serico); digital images: courtesy of Dott. Gianni Penzo Doria. The NTU-ADM
graduate student Xu Peisen created the customary web-based visualisation tool for the 3D model
of the lead seal attached to the parchment with a silken cord and uploaded it on Engineering
Historical Memory in collaboration with the NTU-ADM research assistant Khoi Vu funded by
the Tier 1 grant mentioned above. Last but not least, the research associate Zaqeer Radzi assisted
in formatting the text and the bibliographical references according to the Umanistica Digitale
guidelines under the SGUnited Traineeship Programme.



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