Arius was a leader of the Christian church in Alexandria, Egypt at the time of the Council of Nicaea. His particular view of Christianity was fiercely controversial, and represented one side of the major schism in the church at that time. He and his followers contended that God preceded Jesus Christ and the Holy Spirit. This view was opposed by the eventual "winners" of the Council, led by Athanasius, who believed in a "Holy Trinity" of three constituent parts, neither of which preceded the other.
Interaction with Erimem
Erimem and Peri met him and became convinced that his views were not being fairly heard by either the Emperor Constantine or the Council. Erimem was particularly affected by the leader, whom she called a "man of honour". She strongly disagreed with the Fifth Doctor's decision not to try to change history in Arius' favour. To her, a Pharaoh, Arius was not "history" but "future", and she found his argument and his view of Christianity more appealing than Constantine's. When she was smuggled into the Council by the Doctor, she vastly exceeded her authority to openly plead Arius' case — an action that caused her removal from Council and the Doctor being upbraided by Constantine for creating disharmony.
Nevertheless, Erimem's actions became known to the people of Nicaea and Arius' views, which had only attracted a tiny minority, began to spread. Ultimately, the battle between the two forced Constantine to step away from active participation in the Council, thus turning the matter entirely over to the bishops. Though not exactly wat Erimem had hoped to achieve, Arius viewed her actions as positive to his cause. In fact, when he witnessed the Erimem's departure in the TARDIS, he believed she was an angel, God's "messenger sent to us in our darkest hour".
Later life
After the TARDIS left Nicaea, Arius lost the debate at the Council, despite Erimem's efforts. Constantine exiled him. However, a few years later, Constantine reversed himself, exiling Athanasius, and recalling Arius. Though his views remained unorthodox, he was at least reconciled with his Emperor. (AUDIO: The Council of Nicaea)