Saturnalia was a week-long (Decmeber 17-23) festival to honor the Roman God Saturn. The festival was eventually co-opted by the Church in order to convert the Roman pagans to Christianity and an infallible Pope proclaimed December 25th to be Christ’s birthday even though the Gospels indicate that Jesus was born in the spring.
I’m still looking for a real Christian holiday. Every holiday in the Christian calendar has pagan roots and was appropriated by the Church to convert the pagans. They essentially told them they could keep their festivals and their rituals but added Jesus to them.
Have yourself a Happy Saturnalia!