Very good. and even though it did not go into detail as to why and when there were Christians believing that Jesus was conserved on March 25, I'm glad that he touched on the new information.
Oh as to the missing details: Among intertestamental Jewish traditions included some rabbis thinking at a true prophet would die on his birthday. Another was that a true prophet would die on the anniversary not of his birthday but his conception. This got tied together with another tradition to expect good things on Passover and therefore it was Passover that Sarah became conserved with Isaac, and that it was another Passover that Abraham took Isaac to Mt. Moriah. Jews holding to this tradition saw Isaac as conserved on Passover and born 9 months later, which would be around this time of the year.
In 135 AD the Christians separated from Judaism and they became two separate religions rather than being a sect of Judaism. This time was very much like a divorce. People from both sides having mixed emotions, saying things that hurt the other and being hurt by the other. Beliefs they use to hold in common were divided among them. And they would try to one up the other. This was indeed a sad time in the history of God's people and heaven shed many a tear. Among this was some Christians who looked at the above mentioned Jewish traditions. They said that Isaac was just a type of Jesus and that Jesus was the true antitype and greater. That like Isaac, Jesus was conserved on Passover. Like Isaac, Jesus was born 9 months after Isaac. And that Jesus was indeed true because he died on Passover, the anniversary of his conception. And while Isaac needed a substitute, Jesus is better than Isaac because he is the true sacrifice. The Christians who held to this view started celebrating the feast of the dedication every Passover. One year they decided to stop keeping the Jewish calendar and start keeping the Roman. That year the Roman churches celebrated Passover on March 25 and in Greek churches on April 5. Each year there after instead of keeping the feast of the dedication on Passover they kept it every March 25 or April 5.
In the third century Christians started adding 9 months to March 25 or April 5 and got December 25 and January 5. The days that have become Christmas in the western and eastern churches. This occurred 100 years before the time that we use to think December 25 came into the church. It was believed by Christians who were hiding from Pagans in the catacombs.
So by the time of Constantine in the 4th century there were already Christians who held the birth of Jesus be have been on December 25. Of the articles I've read about this (Mostly Bible Review and Bible Archaeology review) some have suggested that while there were different special days through out paganism around the time of the winter solstice, that they did not focus on December 25 as such. But that when the Christians were a legal religion and had December 25 as the birth of Jesus, that then the other pagans moved their days from around that time to December 25. If this is true, then we did not get December 25 from the Pagans but the took it from the Christians.
Merry Christmas and Happy Hanukkah everyone!!!