It is more probable that Marcellina’s clothing with the religious habit took place during the latter part of this pontificate. For according to the received opinion, St Ambrose was born about the year 340,[326] and thus in 353 he would have been only thirteen years old, and although his sister was older, yet in 353 she would not have been twenty-five, the canonical age for taking the veil.[327] Still it is not impossible that the ceremony and the address of Liberius took place between 352 and 354, and at any rate this much is certain that it took place on the 25th December and not on the Epiphany (6th January), according to the view formerly held.[328] There is no evidence that the Epiphany was observed in Rome, as it had been in the East, as the day of Christ’s birth, and Liberius in this address does not say that the commemoration of the miracles of the loaves and of the changing water into wine was being celebrated precisely on the day of Marcellina’s taking the veil, _i.e._ on the day of the Saviour’s birth (_Natalis Salvatoris_). These things were alluded to only because of their connection with the train of thought followed by Liberius in his address. Nothing can be gathered from the words of Liberius as to when Christmas was first observed in Rome on the 25th December. In any case, it did not come into existence suddenly, but would require time, and, like other festivals, a considerable period would have to elapse before it became general and gained official recognition. Contemporary evidence on this point is wanting; one ancient witness, unfortunately not altogether reliable, speaks of Julius I. and not Liberius as the originator of Christmas. We must now conclude by giving the view we have arrived at. In Rome a distinctive custom had arisen of celebrating Christ’s nativity on the 25th December, while in other quarters it was celebrated on the 6th January. How this was brought about must remain a matter for conjecture. It has been thought that in some places heathen festivals of various kinds were kept in the month of December; in particular, the Kikellia[329] was kept at Alexandria on the 25th December, in Bostra and Pella, a festival of local observance,[330] and in Rome, the Saturnalia began on the 17th December and lasted until the 23rd.[331] It is only natural that the winter solstice should give rise to a festival, and find its place marked in the Calendar of Feasts. Indeed, in the Roman Calendar of much later date—that of Philocalus—the 25th December is marked as the birth-day of the unconquerable Sun-God (_Natalis Solis Invicti_).