Who did Elijah go up against on Mount Carmel?

King Ahab and his wife Jezebel were the evil rulers of the northern kingdom. Elijah 3 years prior proclaimed there would be a drought and no rain, but now God tells Elijah to go and talk to Ahab and there will be rain. Elijah tells Ahab to gather all the prophets of Baal and the prophets of Asherah on Mount Carmel. It was the false prophets of Baal (450) that were killed ( I Kings 18.)