Like
Arius, he was a pupil of
Lucian of Antioch, and it is probable that he held the same views as Arius from the very beginning; he was also one of Arius' most fervent supporters and encourager. It was also because of this relationship that he was the first person whom Arius contacted after the latter was excommunicated from Alexandria by
Alexander I of Alexandria in 321. Apparently, Arius and Eusebius were close enough and Eusebius powerful enough that Arius was able to put his theology down in writing. He afterward modified his ideas somewhat, or perhaps he only yielded to the pressure of circumstances; but he was, if not the teacher, at all events the leader and organizer of the
Arian council. At the
First Council of Nicaea in 325, he signed the Confession, but only after a long and desperate opposition in which he was said to "subscribe with hand only, not heart" according to ancient sources. It was a huge blow to the Arian party since it was surmised that the participants in the
First Council of Nicaea were evenly split between non-Arians and Arians. His defense of Arius angered the emperor, and a few months after the council he was sent into exile due to his continual contacts with Arius and his followers. After the lapse of three years, he succeeded in regaining the imperial favor by convincing Constantine that Arius and his views do not conflict with the proclaimed
Nicene Creed. After his return in 329, he brought the whole machinery of the state government into action in order to impose his views upon the
Church. == Political and religious career ==