Among the witnesses for the old custom, we find Ephrem Syrus, who informs us that, in his time, the church of Mesopotamia commemorated the Incarnation of the Son of God on the thirteenth day after the winter solstice, in the month when the light begins to increase, _i.e._ on the 6th January.[293] It is a well-known fact that the festival of the 25th December, as Christ’s birth-day, was entirely unknown to the ancient churches of Armenia and Mesopotamia, and remained so partially until on in the fourteenth century.[294] In the most of the great churches of the East, on the contrary, this feast was introduced during the last decades of the fourth century, in others somewhat later. Most interesting particulars concerning the introduction of Christmas in various localities are extant, and, since they refer to its _introduction_, we are safe in concluding, from the historical evidence before us, that these churches had not celebrated Christmas until then. This is the case with regard to Constantinople. The second capital of the empire had long been a stronghold of Arianism, so that the orthodox had dwindled down to a mere handful, and no longer possessed a church of their own in the city. During this period Christmas was certainly not celebrated in Constantinople. Not till after the death of Valens, and the elevation of Theodosius the Great to the empire (19th January 379), did the Catholics breathe freely once more. They received as bishop Gregory of Nazianzus, formerly Bishop of Sasima, but then living in retirement at Seleucia in Isauria. He began his labours as a stranger and sojourner in a small private chapel which he called the Anastasia. Here, on the 25th December 379 or 380, Christmas was celebrated for the first time in Constantinople, as he himself informs us, and on this occasion he delivered his thirty-eighth homily.[295] Thus one of the first acts of the restorer of Catholicism in the capital was the introduction of the new festival. In the above homily indeed he says nothing about its being celebrated for the first time, but in the following homily (c. 14), when speaking of the previous Christmas, he calls himself its originator (ἔξαρχος). Gregory’s activity in the capital was unfortunately of short duration. Soon after the meeting of the second General Council, in 381, he was compelled through the intrigues of his opponents to retire from his post.