This is something I've been wrestling with for a while, and I have not been able to come to a conclusion on my own. I've been informed of a lot of similarities between Christ and pagan figures, especially between Him and Horus (as well as Osiris), as well as various Greek and Roman pagan gods. I am sure that this issue has been addressed, but I can't seem to find anything about it. I know there has to be a reason behind this, and would really appreciate any input on this subject. This is something I've been trying to address on my own, but I've thus far been unable to do so.
I will try to explain this as briefly as possible, but it's a rather complicated issue.
During the 1800's-early 1900's, a group of people called Social Darwinists wanted to do several things with our human history:
1. Make it appear as though every major world civilization was founded by "white" "Aryan" peoples.
2. Link the indo-european language group to a perceived racial group.
3. Make it appear as though all major civilizations were originally monotheistic/christian predecessors, who were later "corrupted" by the beliefs of other races.
You may wonder, "what the heck does this have to do with Jesus parallels?" Well, one of the ways they sought to achieve #3 on the above list was to forge and manipulate ancient religious historical documents in order to make it appear as though the Egyptians, for example, were originally monotheistic/proto-Christian. If you don't believe that this was really a trend in the 1800's, open up a copy of the book "Ben Hur" and read the intro section with the discussion by the three Magi. It claims, using the popular "history" of Wallace's day, of course, that the [aryan/white] Egyptians were monotheists who were "corrupted" into polytheism by their black etheopian and nubian neighbors.
There was a poet named Gerald Massey. Without any formal training, he started calling himself an "Egyptologist". He wrote a book referencing several fake sources that outlined parallels between Horus/Osiris and Jesus, including that he had 12 disciples, was crucified, was born of a virgin, etc. No actual Egyptologist today believes any of Massey's fake claims, but virtually all Horus-Jesus claims originate from him. Massey might have been motivated by the Hagelian stream of social Darwinism, a sort of "romantic race/nationalism" that sought to create altered racial/national histories.
To sum up what I've said, in a twist of historical irony, all the forged documents and fake claims made by these social darwinists in an attempt to make Christianity (and, of course, the "Aryans" who believed it, they were quite Eurocentric) look good... these same forged sources and fake claims are being used today by antitheists and occultists to attack Christianity.