"It was near this period that Quadratus, a bishop of the Christians, sent me a defense of his faith"

Saint Quadratus of Athens was bishop of the city until his death in 129 AD. The text of his letter to Hadrian has not survived, but Eusebius, in his Ecclesiastical History (IV, 3) has this to say about it:

1. After Trajan had reigned for nineteen and a half years Ælius Adrian became his successor in the empire. To him Quadratus addressed a discourse containing an apology for our religion, because certain wicked men had attempted to trouble the Christians. The work is still in the hands of a great many of the brethren, as also in our own, and furnishes clear proofs of the man's understanding and of his apostolic orthodoxy. 2. He himself reveals the early date at which he lived in the following words: But the works of our Saviour were always present, for they were genuine:— those that were healed, and those that were raised from the dead, who were seen not only when they were healed and when they were raised, but were also always present; and not merely while the Saviour was on earth, but also after his death, they were alive for quite a while, so that some of them lived even to our day.