 In this proposed arrangement, the two scenes of the Birth and Presentation at the Temple of Mary are visually balanced with each other, whilst the Presentation and the Trial by water above it are concerned with Mary's virginity.Also balanced are the two scenes of offerings on either side of the arch wall; in both cases the figures are placed to make their offerings away from the empty arched space, to keep the visual attention focused within the apse.In 1950, soon after the frescoes were first discovered, a poll of the scholars who attended a conference in Castelseprio showed a rough split between dates in the 7th and 10th century, although the extreme range of dates that have been suggested stretches from the 6th to the 14th century - an almost unprecedented range in medieval art history.