Then, after an interval, Domitian, the son of Vespasian, persecuted the Christians. At this date, he banished John the Apostle and Evangelist to the island of Patmos. There he, secret mysteries having been revealed to him, wrote and published his book of the holy Revelation, which indeed is either foolishly or impiously not accepted by many. And with no great interval there then occurred the third persecution under Trajan. But he, when after torture and racking he found nothing in the Christians worthy of death or punishment, forbade any further cruelty to be put forth against them.
Then under Adrian the Jews attempted to rebel, and endeavored to plunder both Syria and Palestine; but on an army being sent against them, they were subdued. At this time Adrian, thinking that he would destroy the Christian faith by inflicting an injury upon the place, set up the images of demons both in the temple and in the place where the Lord suffered. And because the Christians were thought principally to consist of Jews (for the church at Jerusalem did not then have a priest except of the circumcision), he ordered a cohort of soldiers to keep constant guard in order to prevent all Jews from approaching to Jerusalem.
This, however, rather benefited the Christian faith, because almost all then believed in Christ as God while continuing in the observance of the law. Undoubtedly that was arranged by the over-ruling care of the Lord, in order that the slavery of the law might be taken away from the liberty of the faith and of the church. In this way, Mark from among the Gentiles was then, first of all, bishop at Jerusalem. A fourth persecution is reckoned as having taken place under Adrian, which, however, he afterwards forbade to be carried on, declaring it to be unjust that any one should be put on his trial without a charge being specified against him.
Source: Sacred History (New Advent)