Religion was initially a spark of curiosity, a way of people gathering, and a deep interest into that which is beyond man. It, in a sense, was the first form of science. Maybe there wasn't organized religions or religions as vast as, say, Christianity. But certainly religion has existed for a long, long time. At least several thousand years, not including religious tendencies and behaviors, which can be dated back to prehistory.
No fu.
I'm right, stop arguing. You can't win with your sense against my willpower.