Incorrect. There are multiple pagan December 25th holidays that pre-date Christianity. The entire reason that Christmas is December 25th is because of other pagan festivals. Back in Rome in the good old days there were a lot of pagans who worshipped Isis, Mithra, etc. The winter solstice was thought to be December 25th. In order to make it easier to convert the pagans to Christianity, December 25th was selected so that the pagans could still celebrate a winter festival on the 25th but slowly get them to start doing it in the name of Christianity. Nobody is actually sure when Jesus was born.