Judaism evolved from polytheistic religions, akin to the ones practiced in Assyria, Babylon, and Sumer. Judaism appears to have passed through a Henotheistic stage, where one deity dominated other, lesser deities. read more
They were probably polytheistic. The probably part is honestly mainly hedging. A hopefully uncontentious explanation would be that the ancient israelites, like others in the region, would probably have had a similar pantheon. read more
Thats actually a complex question with a complex answer. Ancient people were all polytheistic. Abraham was the patron of Judaism. Abraham lived in Ur in Mesopotamia, a polytheistic society, and was likely himself polytheistic. read more