See Epiphanius, Hær. lxviii. 1. The arrangement is recognised as one of old standing in the sixth canon of Nicæa, ‘Let the old customs which exist in Egypt, Libya, and Pentapolis remain in force, namely that the Bishop of Alexandria should have authority over all these regions; since this is also customary for the Bishop of Rome. Likewise also at Antioch and in the other prefectures (it is decreed) that their prerogatives should be maintained to those churches.’ The canon points to the natural explanation of the arrangement: the bishops of the capitals began from a very early date to exercise a loosely defined but gradually strengthening supervision over those of the rest of the province. In particular, they came to exercise a veto (and latterly more than a veto) upon the appointments to the provincial sees (εἴ τις χωρὶς γνώμης, ib.). The bishops of Alexandria as well as Rome had even at this date acquired something of the rank of secular potentates (δυναστεία, Socr. vii. 11, ἤδη πάλαι), but not to the extent to which it went later on (ib. 7. and supr. Apol. Ar. §9).