Archibald Bower,
The History of the Popes: From the Foundation of the See of Rome…
“ Hierarchy firstformed. It was in the Pontificate of Sylvester, and under the benign Auspices of Constantine, that the Ecclesiastical Hierarchy was first formed and settled in the Manner it continues to this Day; the new Form of Government, introduced by that Prince into the State, serving as a Model for the Government of the Church. In the Three first Centuries no other Hierarchy was known, no other Degrees thought of, but those of Bishops, Presbyters, and Deacons. Of these alone was composed the whole Body of the Clergy ”
