At first, he sympathized with the Anomoean Arians, among whom was his metropolitan, Acacius of Caesarea. Later, he broke away from them for both jurisdictional and theological reasons and aligned himself with the semi-Arian Homoiousians. This shift brought him persecution and exile. Eventually, he accepted the Nicene faith, though he always avoided using the term homoousios (consubstantial) when referring to the Word of God in relation to the Father.
Because of these fluctuations, it took a long time for Cyril’s personal holiness to be universally recognized. In the West, his feast day wasn’t established until 1882. He participated in the First Ecumenical Council of Constantinople, where the Council affirmed the legitimacy of his episcopate, which had been questioned by his opponents.
Cyril is particularly famous for his beautiful catecheses, preserved thanks to the notes of a stenographer. These writings earned him the title of Doctor of the Church, conferred by Pope Leo XIII. He died in 386 or the following year. The feast day of March 18 has been celebrated since ancient times in Jerusalem (5th century) and throughout the East.
