5 myths about the Christmas Story. Coming in at number one. Jesus was born on December 25th. We celebrate Christmas on December 25th. So isn’t it logical to think that Jesus was born on that day? The reality is that actually we don’t know exactly when Jesus was born. Scholars offered different dates. Some have suggested that December 25th was picked because that was a pagan holiday “Sol Invictus”. One explanation is that it was believed that Mary conceived on March 25th, move forward 9 months, end up on December 25th. The bottom line is we don’t know exactly when Jesus was born but we choose to celebrate it on December 25th nonetheless.