Numerous arguments point to the fact that the major role in the Christianization of the Serbs had priests and missionaries from Rome, rather than from the closer Constantinople. This can also be seen in the earliest Christian terms in the Serbian language which came from the Latin language ("oltare" from "altare", altar), the earliest Christian toponymy and presence of several religious feasts and holidays which corresponded to the dates in the calendar of the Roman Catholic Church - St. Vitus' Day ("Vidovdan"), Michaelmas ("Miholjdan"), Theodore the Studite ("Mratindan"). Confirmation of the early missionary work by Rome, already in the 7th century, are writings of Pope Agatho and Thomas the Archdeacon. This wasn't unusual, as, following the ancient rules, this region of the still unified church was administered by Rome. This began to change after 732, when Byzantine emperor Leo III the Isaurian began to transfer regions and cities to the jurisdiction of the Ecumenical Patriarchate of Constantinople, including some parts of the Balkans. Despite this, the division wasn't as sharp as it will become after the East–West Schism in 1054.