This Cassianus is mentioned twice by Clement: once in Strom. I. 21, where Clement engages in a chronological study for the purpose of showing that the wisdom of the Hebrews is older than that of the Greeks, and refers to Cassian’s Exegetica and Tatian’s Address to the Greeks as containing discussions of the same subject; again in Strom. III. 13 sqq., where he is said to have been the founder of the sect of the Docetæ, and to have written a work, De continentia or De castitate (περὶ ἐγκρατείας ἢ περὶ εὐνουχίας), in which he condemned marriage. Here, too, he is associated with Tatian. He seems from these references to have been, like Tatian, an apologist for Christianity, and also like him to have gone off into an extreme asceticism, which the Church pronounced heretical (see Bk. IV. chap. 29, note 4). Whether he was personally connected with Tatian, or is mentioned with him by Clement simply because his views were similar, we do not know, nor can we fix the date at which he lived. Neither of his works referred to by Clement is now extant. Jerome (de vir. ill. chap. 38) mentions the work which Eusebius speaks of here, but says that he had not been able to find a copy of it. It is called by Clement, in the passage referred to here by Eusebius, ᾽Εξηγητικοὶ, and so Eusebius calls it in his Præf. Evang. X. 12, where he quotes from Clement. But here he speaks of it as a χρονογραφία, and Jerome transcribes the word without translating it. We can gather from Clement’s words (Strom. I. 21) that the work of Cassianus dealt largely with chronology, and hence Eusebius’ reference to it under the name χρονογραφία is quite legitimate.