An important holiday for Christianity to commemorate the birth of Jesus. Also known as Jesus Christmas, Nativity, Catholic also known as Jesus Christmas Feast. The date of Jesus' birth is not recorded in the Bible. The Roman Church began to celebrate this festival on December 25 in 336 AD. December 25 was originally the birthday of the sun god prescribed by the Roman Empire. Some people think that they choose to celebrate Christmas on this day because Christians believe that Jesus is the righteous and eternal sun.