@NearMiss: I wouldn't say that's entirely true whilst knowing there are some facts which bear up to what you say. Yes, it was the very last day of a pagan ceremony but it was by method that Christianity crept into December 25th.
(Sorry in advance for the long reply ... )
December 25th was a day that had many meanings but was adopted by Christian's as the date of Christ's birth. On that same date, the practice of Saturmalia was celebrated (week long period of wickedness and debauchery) which extended from 17 up to 25 December so, in effect, Christmas day was the last day of Saturmalia. However, Christians at that time knew what they were doing and in effect 'hijacked' that last day but it was hardly a success:
Christians had little success, however, refining the practices of Saturnalia. As Stephen Nissenbaum, professor history at the University of Massachussetts, Amherst, writes, [i]“In return for ensuring massive observance of the anniversary of the Saviour's birth by assigning it to this resonant date, the Church for its part tacitly agreed to allow the holiday to be celebrated more or less the way it had always been.”{/i}
Christianity 'crept' into December 25th. It's how Christians tried to hold a religious celebration within Saturmalia which didn't hold true, whilst in the end Christmas itself was accepted to be what it was turned into. It's well accepted that Christ was not born on December 25 from biblical context and manuscripts found over the years; some would argue that, if nothing else, it's one day where people remembered his birth and take it for what it's worth.
