Around 400 [AD], the Roman emperor Theodosius decided the Olympic Games were too pagan in nature, and banned them completely. This was part of the Roman Empire’s shift towards Christianity. During Theodosius’ youth, he was tutored by the bishop Ambrose of Milan. Theodosius passed a number of laws that were designed to eliminate Greco-Roman paganism completely, as well as doing away with the rituals and ceremonies that celebrated the old pagan religions of Greece and Rome. To make Christianity the state religion, all vestiges of the old ways had to be eliminated, and that included the Olympic Games.
My two cents
I think of that verse in the book of Jeremiah which says not to follow the ways of the heathen. In that context, I guess the Olympics would fall into this category as well. It would be convenient to find a page on the interwebs which lists all of the customs in our current society which are actually based on paganism. I understand birthdays are one such custom, but the Christians I’m surrounded by don’t seem to care, and I feel like the odd man out because of it.
Wigington, P. (n.d). Pagan Origins of the Olympic Games. Available: http://paganwiccan.about.com/od/greekdeities/a/PaganOlympics.htm. Last accessed 2nd Oct 2012.