It was the moment when Catholics began successfully to repel Arianism; it was just those who attacked Arianism with most vigour and success who promoted the spread of the new festival in the East. We must add to this the evidence afforded by secular enactments. Neither the laws of Valentinian II., nor the revisers of the _Codex Theodosianus_ in 438, nor the _Breviarium Alaricianum_ of 506, regard the 25th December as a festival established by law. It was made to appear for the first time as such by Tribonianus in the _Codex Justinianus_.[301] From these additional facts, we gather that Christmas was of later introduction in the Church than Easter or Whitsunday. In such matters secular law generally follows the lead of ecclesiastical law. If Christmas had been celebrated in the Church from the beginning, one can see no reason why it should not have enjoyed equal privileges with Easter and Whitsunday. Still there was a law of the Emperor Arcadius as early as 400 which included Christmas among the days on which at least the games of the circus were forbidden.[302] Chrysostom, in the sermon referred to above, states plainly that, at the time when the attempt was being made to introduce the festival in the East, it was already celebrated in Rome. Our attention is thus naturally directed to Rome, and it will be interesting to learn how long it had been so observed there. This question we must now consider more fully. John, Bishop of Nicæa, informs us that the Roman Church had begun under Pope Julius I. (337-352) to celebrate the birth of our Lord on the 25th December.[303] This pope, with the assistance of the writings of Josephus, had ascertained that Christ was born on the 25th December. John of Nicæa then recurs substantially to the reckoning which we have already produced from Chrysostom, according to which the appearance of the angel to Zachary in the Temple happened on the 23rd September and the Annunciation on the 25th March. From these data it followed as a matter of course that the 25th December was the day of Christ’s birth. John had gained this information from an alleged correspondence between Cyril of Jerusalem and Julius, from which he quotes. But this correspondence is certainly not authentic, as will appear from one of the facts quoted from it further on.[304] But the fact that it cannot stand the test of criticism does not prove the spuriousness of the treatise of John of Nicæa in itself, nor the incorrectness of everything else contained in it.