In his book De caerimoniis aulae Byzantinae ("Book of Ceremonies"), Emperor Constantine VII (913–919) wrote a detailed account of the ceremonies held in the Hagia Sophia by the emperor and the patriarch.
Iti librona iti De caerimoniis aulae Byzantinae ("Libro dagiti Seremonia"), ni Emperador Konstantino VII (913–919) ken nagsurat iti nasalaysayan a panaglagip kadagiti seremonia a naaramid idiay Hagia Sophia babaen ti emperador ken ti patriarka.