Many Christmas traditions come from a Roman holiday honoring what god?
The ancient Roman festival of Saturnalia, which honored the agricultural god Saturn, is the source of many modern Christmas traditions. To start, Saturnalia was celebrated during the winter solstice, which at the time fell on the Julian calendar's December 25. During the festival, Romans decorated their homes with greenery, didn't work, exchanged gifts, and feasted, all of which are part of Christmas celebrations today.
Source: History.com