Why do christians consider december 25 to be a holy day?

This date was selected as the birth day of jesus in around 300 ad, before that it was 6 january, 1 may and other dates. 25 december has been chosen because a lot of the gods in the mediterranean region were celebrated on 25 of december so it was easier to convert people to christianity because they already celebrated that day as the birth day of a god. examples of gods born on 25 december. roman religion...attis, greek religion... dionysus, persian religion mithra , all of these religions predated christianity