There have been many many religions throughout history. Most have died out or been subsumed into other religions. We don't even know what most early religions might have been like. There are many indications though of what seems to be religious practices going back to times in the 10-12,000 year period, other very strong indication going back many tens of thousands of years. There are also the religions of Egypt and the other civilizations of the near East.
If we limit the question to living religions then the Hindu faith is probably the oldest, followed by Judaism.
Aslan is not a Tame Lion