On December 25, SOME Christians around the world will gather to celebrate Jesus birth.
The original Christian Church, The One Holy Catholic and Apostolic Church, celebrates the birth of Jesus on January 7th.
The Roman Catholic church, which broke away from the Orthodox Church and later the Church of England that broke from the Roman Catholic Church and the Protestant Churches resulting from Martin Luthers theses celebrate the birth of Jesus on December 25th.
The original Christian Church, The Eastern Orthodox Church remains unchanged since Pentecost.
No, they celebrate it on December 25th as well. We just don't all agree what day December 25th is.