The origin of Christmas:
Many people falsely believe that the date of Christmas comes from a Roman holiday. There was a Roman holiday on Dec. 25th, celebrating the return of light to the world; Dec. 25th is the first day at which the Romans could discern the lengthening of days following the Winter Solstice. But Christmas actually has an origin which predates the Roman Empire.
After the Babylonian catptivity, The Jewish Temple was re-established by Cyrus, King of Persia. Cyrus was a just emporer, but he was conquered by Alexander the Great. After Alexander's death, his empire was divided among three factions, with the Selucids inheriting Israel. The Selucids tried to form the Jews into idolatry. THey set up a great abomination in the Temple, and defiled it in every way imaginable. The Jews revolted.
As they went to battle, the Jews were promised by a prophet that any faithful Jew would be spared death in the upcoming battle. The Jews triumphed, but many were slain. Those who were killed were found to have had amulets on their person. Their mourning friends, who had come to believe in the resurrection of the dead, wept that their comrades had fallen into sin. Rather than keep the enormous bounty of their victory over the Selucids, they donated to the temple all they had won in atonement for the sins of their comrades.
With the great wealth won in battle, they were able to cleanse the Temple, refurbish it, replace the desecrated altar, and adorn it fully according to the commands given to Moses. On that day, the spirit of God was said to return to the Temple, and that day became known as the Feast of the Dedication.
Jesus proclaimed himself to be the Temple of God. Hence, his birthday was the day that God dwelt in his Temple, and his birthday became linked to the Feast of the Dedication, which occurred on the 25th day of the Jewish month closest to December.
When Jesus died on the cross, the Spirit of God left its Temple; As a sign, the curtains of the Jewish Temple were torn, and the altar cracked. But on Pentecost, it returned to dwell on Earth in His Church. It shall never depart from us again.
Cyrus who permitted the Jews to return from babylon is different from the guy who Alexander conquered. Just off the top of my head, there was a guy named Darius and Xerxes who fought the Greeks at Marathon and Salamis. Of course names repeat in dynasties, don't they.