In 319, he became a deacon, and even in this capacity he was called upon to take an active part against the rising heresy of Arius, an ambitious priest of the Alexandrian Church who denied the Divinity of Christ. This was to be the life struggle of St. Athanasius.
In 325, he assisted his Bishop at the Council of Nicaea, where his influence began to be felt. Five months later Alexander died. On his death bed he recommended St. Athanasius as his successor. In consequence of this, Athanasius was unanimously elected Patriarch in 326.
His refusal to tolerate the Arian heresy was the cause of many trials and persecutions for St. Athanasius. He spent seventeen of the forty-six years of his episcopate in exile. After a life of virtue and suffering, this intrepid champion of the Catholic Faith, the greatest man of his time, died in peace on May 2, 373. St. Athanasius was a Bishop and Doctor of the Church.