Fifth: The Dates of Gods’ Birth, Worship, and Traditions
Not only do Christian beliefs correspond with other religions on some issues, but also on worshipping and dates as well. The idolatrous believe, in spite of the differences of their gods, that their incarnated gods were born on 25th of December, such as the god Mithra and others.
That is what the Orthodox Christians say of their dates. It was fixed in 530 C.E. by the priest Deunesus. He wanted to draw Christians away from the idolatrous celebrations, and occupy them with Christian celebration. The same happened in many other idolatrous celebrations, so the Christians took the dates and the traditions from them.
In his book, “The History of the Anglican Church”, Priest Beid quoted Pope Gregory’s first speech, (601C.E), in which he quoted Pope Mellitus’s advice, which forbade the destruction of the idolatrous temples. In addition, he believed in turning them away from worshipping the devil to worship the true God, to clean the people’s hearts of sins, and make it easier for them to visit the temples, which they used to visit. 
Thus, the new Christian will not find any difference, in the place or the content, between Christianity and what he/she believes, which will make it easier to spread Christianity.
- Frank Discussion Between the Servant of Allah and the Servant of Christ, Abdul Wadoud Shalaby, pp 67-72, Christianity, Ahmad Shalaby, pp 83, The True Christianity That Christ Taught, Alaa Abu Bakr, pp 191-192