Except to say that assimilating native heathen religious observances was only a means of inducing their adoption of Christianity. Tom and/or Larry can (and surely will) correct me if I am wrong, but I am fairly certain the Roman Catholic Church had long been celebrating the Saviors birth before condoning its association with evergreen trees, holly wreathes and other existing heathen winter religious observances. Indeed, at least one source claims even the Roman festival for Sol Invictus began as a deliberate imperial attempt to coopt an increasingly important Christian holiday into pagan rites.