Introduction.

A. Testimonies.

The most important testimonies¹ regarding Clement of Alexandria, apart from his own writings, are the following:
Julius Africanus² in the Chronicle (according to Cedrenus, Hist. comp. p. 251 C edit. Paris; I p. 441, 9 Bonn; see Routh, Reliquiae sacrae II² p. 307): "In the time of Commodus, Clement the Stromatist was known in Alexandria."
Alexander of Jerusalem in Eusebius, H. E. VI 11, 6: "I sent these letters to you" (the letter to the church in Antioch, written around the year 211) "by the hand of Clement, the blessed presbyter, a man of virtue and approved, whom you know and will come to know; who, having been here by the providence and supervision of the Master, strengthened and increased the church of the Lord." And in Eusebius, H. E. VI 14, 9 (letter to Origen): "For we know those blessed fathers who have gone before us... the holy Clement, who was my master and who benefited me."
The author of the Little Labyrinth (Hippolytus) in Eusebius, H. E. V 28, 4: "And there are also letters of certain brethren, older than the times of Victor, which they wrote against the heresies of that time on behalf of the truth, I mean those of Justin, Miltiades, Tatian, Clement, and many others, in all of which Christ is spoken of as God."
Eusebius, H. E. V 11, 1f: "In his time" (referring to Pantaenus, see Zahn, Suppl. Clem. p. 172¹) "he" (Clement) "was exercised in the divine scriptures in Alexandria..."

Sylburg already collected some reports about Clement in his edition (1592); subsequent editors have increased the collection. The most complete collection of testimonies was made by E. Preuschen in Harnack's Überlieferung p. 296 ff. The text above is essentially a reproduction of his collection.
Cf. H. Gelzer, Sextus Julius Afric. and Byzantine Chronography I p. 280.