Alexander , St., bp. of Byzantium, as the city was then called (Theod. Hist. i. 19) for about 23 years, his consecration being variously dated from A.D. 313 to 317. He was already 73 years old at the time (Socr. Hist. ii. 6; Soz. Hist. iii. 3). He is highly praised by Gregory of Nazianzum ( Or. 27), and by Epiphanius ( adv. Haer. lxix. 10). Theodoret calls him an "apostolic" bishop ( Hist. i. 3, cf. Phil. 12). In the commencement of the Arian troubles the co-operation of Alexander was specially requested by his namesake of Alexandria (Theod. i. 4); and he was present at the council of Nicaea (Soz. ii. 29). When Constantine, induced by the Eusebians (Athan. Ep. ad Serap.; Rufinus, Hist. i.), and deceived by the equivocations of Arius (Socr. i. 37), commanded that Arius should be received to communion, Alexander, though threatened by the Eusebians with deposition and banishment, persisted in his refusal to admit the archheretic to communion, and shut himself up in the church of Irene for prayer in this extremity. Alexander did not long survive Arius (Socr. ii. 6; Theod. i. 19). On his death-bed he is said to have designated Paulus as his successor, and warned his clergy against the speciousness of Macedonius.