From The Life and Times of Bruce Gerencser:
…before Israelite religion denied the existence of other Gods than Yahweh, it went through a phase of granting their existence but condemning their worship (by Israelites, at least; if the Moabites wanted to worship Chemosh, that was their business). In technical terms, Israelite religion reached monotheism only after a period of “monolatry” — exclusive devotion to one god without denying the existence of others.
This much is accepted by most Biblical scholars, including some who are believing Jews or Christians. But things get more controversial when you suggest that there was a long time when even “monolatry” was too strong a word from mainstream Israelite doctrine — a time when not all non-Yahweh gods were considered evil or alien; a time when Yahweh was ensconced in an Israelite pantheon, working along side other gods.
Yet, if you read the scriptures closely, you’ll soon see hints of such a time.