The Bible is very clear: there is an invisible spirit world, in which spiritual powers operate (Eph 6:12).
The nation of Israel got into an alliance with another nation, the Sidonians, by marriage. He married Jezebel, and immediately opened his life to the influence of the spirit power behind her. Her father was a priest of Baal, and so she introduced the worship of Baal and Ashtaroth.
Keywords: Ashtaroth, Baal, Sidonian, influence, king, israel, spirit world, Jezebel, Slumber, sleep