What religions did Plato and Socrates practice?
** I'm trying to learn the history of different religions, and how they originated.
If you're interested in the origin of religions then you won't find it with the great greek philosophers of the time. Or of any other philosophers for that matter. These great thinkers of their time were not so concerned with worship as they were about knowledge in general.
The oldest and eastern religions, Hinduism from which Buddhism was derived. Then came Judaism from which came Christianity. And the youngest is Islam. Those are the main ones.
My answer is not incomplete. I gave a very short run down because I don't like to write long pages on here. You can look any one of the religions up on the net or in books/library.
They both predate Christianity. The religion of ancient Greece was Pagan (like Zeus, Athena, Aphrodite, Hades...)