Check here: https://www.reddit.com/r/AskHistorians/comments/5mfsvd/what_was_mohammads_religion_before_islam/dc3cdy0?utm_medium=android_app&utm_source=share&context=3

As it touches on about pre-Islamic/ pre-Mohammed faiths that were common in the arab world before Mohammed.

In a nutshell, from what is generally understood and accepted, Mohammed was a member of the Quraysh tribes in Arabia, born in Mecca. At the time, the members were polytheists and diviners.

Edit: Comment History Credit: u/frogbrooks