We do not know who those men were, but their legacy was the so-called Donation of Constantine, a forged document that purported to be a grant form the first Christian emperor to the bishop of Rome, giving him jurisdiction over the whole Western empire. It was frequently used by later popes to support their claims, not least in the quarrel with Cerularius. The donation was followed in about 850 by a compilation of papal pronouncements now known as the False DecretalsGod Has Spoken, 782
In the year 533 the Byzantine Emperor Justinian recognized the primacy of the bishop of Rome over the occupants of the other patriarchal sees. Gregory the Great still refused the title 'Universal Bishop', but in 607 it was conferred on his successor, Boniface III, who had no scruples in accepting it. From this time on the spiritual primacy of the succeeding bishops of Rome was generally honoured in the West, through strenuously resisted in the East. It marks the beginning of PoperyThe History of Christian Doctrines (232)