Christmas is primarily celebrated on December 25th each year. It is an annual festival commemorating the birth of Jesus Christ. This date was fixed by the church in the early fourth century and aligns with the winter solstice in the Roman Empire. While most Christians celebrate on December 25th according to the Gregorian calendar, some Eastern Christian churches observe Christmas on January 7th, which corresponds to December 25th in the older Julian calendar. The celebration also includes various cultural customs and traditions and is a public holiday in many countries around the world.