Bp. of Nicomedia, the leader of the Arian party. When Arius turned to him after his condemnation by Alexander, Bp. of Alexandria, Eusebius was already Bp. of Nicomedia, and he used his influence at court on Arius' behalf. He was exiled soon after the Council of Nicaea (325), but on his return in 328/9 he led the struggle against Athanasius. In 337 he baptized the dying Constantine. Translated to Constantinople in 339, in 341 he assembled the Dedication Council at Antioch which marked the beginning of the ascendancy of Arianism.