Description: Christmas, also referred to as Christmas Day or Christmastide, is an annual holiday celebrated on December 25 that marks and honors the birth of Jesus of Nazareth. His birth, which is the basis for the anno Domini system of dating, has been determined by modern historians as having occurred between 7 and 2 BC. The date of celebration is not thought to be Jesus' actual date of birth. It may have been chosen to coincide with the winter solstice, which the ancient Romans celebrated on December 25.