Library Eusebius of Caesarea Church History
Book 2, Chapter 24: Annianus the First Bishop of the Church of Alexandria after Mark.
1. When Nero was in the eighth year of his reign, Annianus succeeded Mark the Evangelist in the administration of the parish of Alexandria.
English translation by Arthur Cushman McGiffert, in Nicene and Post-Nicene Fathers, Series II, Vol. I (eds. Philip Schaff and Henry Wace; Buffalo: Christian Literature Publishing Co., 1890). Public domain. Digital text via New Advent Church Fathers.