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.

The East–West Schism, also known as the Great Schism or the Schism of 1054, is the break of communion between the Catholic and Eastern Orthodox churches since 1054. A series of ecclesiastical differences and theological disputes between the Greek East and Latin West preceded the formal split that occurred in 1054. Prominent among these were the procession of the Holy Spirit (Filioque), whether leavened or unleavened bread should be used in the Eucharist, iconoclasm, the coronation of Charlemagne as Emperor of the Romans in 800, the Pope's claim to universal jurisdiction, and the place of the See of Constantinople in relation to the pentarchy.