Jesus was one of many holy figures "born" on the 25th of December

Just finished watching an independent documentary written and directed by Brian Flemming called "The God Who Wasn't There" which questions the existence of Jesus. The documentary itself was disappointing as I felt the writer was pushing his own agenda a bit too intensely. Rather than discussing the details, historical facts and proof outlining his arguments, he spends too much time being bitter about his religious upbringing. On the whole, the documentary felt childish and amateur to me.

However, like any other documentary, it wasn't totally a lost cause because its thesis was extremely interesting. For one thing, I actually had no idea that there is lot of controversy regarding the birthday of Jesus, let alone the fact that there is an intense ongoing debate regarding his very existence. And after researching the topic a little on the Internet, I felt a bit stupid as both these controversies so popular, that every theist needs to know about them. One website considers the birthday of Jesus as one of history's 20 greatest historical myths:

Christmas is meant to celebrate the birth of Jesus, but there is no evidence whatsoever, biblical or otherwise, that He was actually born on that day. Nor is there anything to suggest that He was born in a manger, or that there were three wise men (although, as any nativity play will remind you, three gifts were mentioned). There are differing views as to why December 25 was chosen as Christmas day, but one of the most interesting is that the day was already celebrated by followers of Mithras, the central god of a Hellenistic cult that developed in the Eastern Mediterranean around 100 BC. The followers of this faith believed that Mithras was born of a virgin on 25 December, and that his birth was attended by shepherds...

In fact, it seems that there are several other historical pagan deities besides Mithras "born" on December 25. According to research done by this website, they are: 

Horus
Attis
Dionysus the son of Zeus
Tammuz
Hercules
Perseus
Helios
Bacchus
Apollo
Jupiter
Sol Invictus - (The "Unconquered Sun")

That's quite a few pagan Gods. So apparently around the 4th century AD, the Catholic church just adopted this traditional pagan holiday of December 25th as the birthday of Jesus. Fair enough!