NPNF2-01. Eusebius Pamphilius: Church History, Life of Constantine, Oration in Praise of Constantine

Chapter VI.—Clement of Alexandria.

Clement¹⁸⁰³ having succeeded Pantænus,¹⁸⁰⁴ had charge at that time of the catechetical instruction in Alexandria, so that Origen also, while still a boy,¹⁸⁰⁵ was one of his pupils. In the first book of the work called Stromata, which Clement wrote, he gives a chronological table,¹⁸⁰⁶ bringing events down to the death of Commodus. So it is evident that that work was written during the reign of Severus, whose times we are now recording.