Humbert of Silva Candida, O.S.B., also known as Humbert of Moyenmoutier was a French Benedictine abbot and later cardinal. It was his act of excommunicating the Patriarch of Constantinople, Michael I Cerularius, in 1054 that is generally regarded as the precipitating event of the East–West Schism between the Roman Catholic Church and the Eastern Orthodox Church.

Hagia Sophia, officially the Hagia Sophia Grand Mosque, is a mosque, a former church, and a major cultural and historical site in Istanbul, Turkey. The last of three church buildings to be successively erected on the site by the Eastern Roman Empire, it was completed in 537 AD. The site was an Chalcedonian church from 360 AD to 1054, an Orthodox church following the Great Schism of 1054, and a Catholic church following the Fourth Crusade. It was reclaimed in 1261 and remained Eastern Orthodox until the fall of Constantinople in 1453. It served as a mosque until 1935, when it became a museum. In 2020, the site once again became a mosque.