The origin of Christmas is related to the ancient Roman festival of Saturnalia and the birthday of the sun god. In 336 AD, the Roman Church began celebrating this festival on December 25, which was originally designated as the birthday of the sun god by the Roman Empire. Some believe that choosing this day to celebrate Christmas was because Christians regarded Jesus as the righteous and eternal sun.
Christmas is an important holiday in Christianity to commemorate the birth of Jesus, also known as Jesus' Christmas or Nativity Day. In Catholicism, it is also known as the Feast of Jesus' Christmas. In 336 AD, the Roman Catholic Church began celebrating this festival on December 25th. December 25th was originally designated as the birthday of the sun god by the Roman Empire. Some people believe that choosing this day to celebrate Christmas is because Christians believe that Jesus is the righteous and eternal sun. After the mid-5th century, Christmas, as an important holiday, became a tradition of the church and gradually spread among Eastern and Western churches. Due to different calendars and other reasons, the specific dates and forms of celebration held by various religious sects also vary.

In addition, the origin of Christmas is also related to the Roman festival of the god of agriculture. The Agricultural God's Day is a holiday celebrated by the ancient Romans to welcome the New Year, traditionally from December 17th to December 24th. In the 3rd century AD, Roman Emperor Domitian changed the festival of the god of agriculture to be held on December 25th. After the prevalence of Christianity in the Roman Empire, the Holy See incorporated this folk festival into the Christian system to celebrate the birth of Jesus.
The spread of Christmas customs to Asia mainly occurred in the mid-19th century, with Japan, South Korea, and other countries being influenced by Christmas culture. Nowadays, it has become a common custom in the West to exchange gifts, hold feasts, and add festive atmosphere with Santa Claus, Christmas trees, etc. during Christmas. Christmas has also become a public holiday in the Western world and many other regions.

