Jezebel was the daughter of King Ethbaal of the city states of Sidon and Tyre. They were Phoenicians, a sea faring people. Baal was their god. Astarte was their goddess.
Because she was a Phoenician, Princess Jezebel was educated, well-traveled, talented, and quick witted. Researchers wonder why she is so reviled in the Hebrew Testament. Was it because she was a woman of royal power, having vast legal and business knowledge?
Other objections were her devotion to Baal and Astarte. All foreign wives of kings were allowed to bring their religion with them. But she did not bring her gods to Israel. King Omri and his son Ahab were Baal worshippers before she arrived. The Bible authors avoided giving her the title of Queen, even though she was the queen, being married to King Ahab. And there is no evidence she was ever unfaithful to King Ahab.