Long before the fourth century, and long before the Christian era itself, a festival was celebrated among the heathen, at that precise time of the year, in honor of the birth of the son of the Babylonian queen of heaven; and it may fairly be presumed that, in order to conciliate the heathen, and to swell the number of the nominal adherents of Christianity, the same festival was adopted by the Roman Church, giving it only the name of Christ. This tendency on the part of Christians to meet Paganism halfway was very early developed; and we find Tertullian, even in his day, about the year 230, bitterly lamenting the inconsistency of the disciples of Christ in this respect, and contrasting it with the strict fidelity of the Pagans to their own superstition (ibid., p. 93).  

Long before the fourth century, and long before the Christian era itself, a festival was celebrated among the heathen, at that precise time of the year, in honor of the birth of the son of the Babylonian queen of heaven; and it may fairly be presumed that, in order to conciliate the heathen, and to swell the number of the nominal adherents of Christianity, the same festival was adopted by the Roman Church, giving it only the name of Christ. This tendency on the part of Christians to meet Paganism halfway was very early developed; and we find Tertullian, even in his day, about the year 230, bitterly lamenting the inconsistency of the disciples of Christ in this respect, and contrasting it with the strict fidelity of the Pagans to their own superstition (ibid., p. 93).