The importance of Quadratus’ Apology in the mind of Eusebius is shown by his beginning the events of Hadrian’s reign with it, as well as by the fact that he gives it also in his Chronicle, year 2041 of Abraham (124 to 125 a.d.), where he calls Quadratus “Auditor Apostolorum.” Eusebius gives few events in his Chronicle, and therefore the reference to this is all the more significant. We find no mention of Quadratus and Aristides before Eusebius, and of the Apology of Quadratus we have only the few lines which are given in this chapter. In the Chronicle Eusebius says that Quadratus and Aristides addressed apologies to Hadrian during his stay in Athens. One ms. of the Chronicle gives the date as 125 a.d. (2141 Abr.), and this is correct; for, according to Dürr (Die Reisen des Kaisers Hadrian, Wien, 1881, p. 42 to 44, and 70 to 71), Hadrian was in Athens from the fall of 125 to the summer of 126 and from the spring of 129 to the spring of 130. Eusebius adds in his Chronicle (but omits here) that these apologies were the cause of a favorable edict from Hadrian, but this is incorrect. Eusebius (IV. 12) makes a similar statement in regard to the Apology of Justin, making a favorable edict (which has been proved to be unauthentic) of the Emperor Antoninus the result of it. (See Overbeck, Studien zur Geschichte der alten Kirche, I. 108 sq., 139.) Quadratus and Aristides are the oldest apologists known to us. Eusebius does not mention them again. This Quadratus must not be confounded with Quadratus, bishop of Athens in the time of Marcus Aurelius, who is mentioned in chap. 23; for the apologist Quadratus who belonged to the time of the apostles can hardly have been a bishop during the reign of Marcus Aurelius. Nor is there any decisive ground to identify him with the prophet mentioned in Bk. III. chap. 37 and Bk. V. chap. 7, for Quadratus was a very common name, and the prophet and the apologist seem to have belonged to different countries (see Harnack, Ueberlieferung der griech. Apol. p. 103). Many scholars, however, identify the prophet and the apologist, and it must be said that Eusebius’ mention of the prophet in III. 37, and of the apologist in IV. 3, without any qualifying phrases, looks as if one well-known Quadratus were referred to. The matter must remain undecided. Jerome speaks of Quadratus and Aristides once in the Chronicle, year 2142, and in de vir. ill. chap. 19 and 20. In chap. 19 he identifies Quadratus, the apologist, and Quadratus, the bishop of Athens, but he evidently had no other source than Eusebius (as was usually the case, so that he can very rarely be accepted as an independent witness), and his statements here are the result simply of a combination of his own. The later scattering traditions in regard to Quadratus and Aristides (chiefly in the Martyrologies) rest probably only upon the accounts of Eusebius and Jerome, and whatever enlargement they offer is untrustworthy. The Apology of Quadratus was perhaps extant at the beginning of the seventh century; see Photius, Cod. 162. One later tradition made Quadratus the angel of Philadelphia, addressed in the Apocalypse; another located him in Magnesia (this Otto accepts). Either tradition might be true, but one is worth no more than the other. Compare Harnack, Die Ueberlieferung der griech. Apol., and Otto, Corpus Apol. Christ. IX. p. 333 sq.