Origins of Christmas
Christmas's roots can be found in both Roman and paganic cultures. In reality, the Romans observed two holidays in December. The first was Saturnalia, a two-week celebration in honor of their agricultural god Saturn. They celebrated the birth of Mithra, their sun god, on December 25. Both occasions were rowdy, intoxicated parties.
In order to dispel the darkness, the pagan cultures also lit bonfires and candles in December, which also happens to be the month with the darkest day of the year. The Romans included this custom in their own festivities as well.
As Christianity spread throughout Europe, Christian clergy were unable to put a stop to pagan customs and celebrations. Because no one knew when Jesus was born, they adapted a pagan ritual into a celebration of His birthday.