How did christ get into Christmas?

Answer:
In the 4th century, just after Christianity became the official religion of the Ancient Roman Empire, Christmas (then called "Feast of the Nativity of the Christchild") was created and placed on December 25 in an effort to replace the existing pagan holiday, "Dies Natalis Solis Invicti" (English: Birth of the Unconquered Sun God) with a Christian holiday.
First answer by CrazyInSane. Last edit by CrazyInSane. Contributor trust: 1 [recommend contributor recommended]. Question popularity: 1 [recommend question].