Why do people think that Jesus is born on December 25?

The belief that Jesus was born on December 25 stems from early Christian tradition and the alignment of this date with pagan winter solstice celebrations, such as the Roman festival of Saturnalia. In the 4th century, church leaders may have adopted this date to facilitate the conversion of pagans to Christianity. Although The Bible does not specify a date for Jesus' birth, December 25 became widely accepted over time, symbolizing the arrival of light in the darkness of winter.