2 Kings 11:17,18 (KJV)
17 And Jehoiada made a covenant between the Lord and the king and the people, that they should be the Lord’s people; between the king also and the people.
18 And all the people of the land went into the house of Baal, and brake it down; his altars and his images brake they in pieces thoroughly, and slew Mattan the priest of Baal before the altars. And the priest appointed officers over the house of the Lord.
2 Kings 11
Joash Was Protected And Became King
Joash was protected from Athaliah and at seven years old became king. This is when all the altars of baal were destroyed.