Manasseh was 12 years old when he became king; he reigned 55 years in Jerusalem.
References for 2 Chronicles 33:1
He did what was evil in the Lord's sight, imitating the detestable practices of the nations that the Lord had dispossessed before the Israelites.
He rebuilt the high places that his father Hezekiah had torn down and reestablished the altars for the Baals. He made Asherah poles, and he worshiped the whole heavenly host and served them.
References for 2 Chronicles 33:3
He built altars in the Lord's temple, where the Lord had said: "Jerusalem is where My name will remain forever."
He built altars to the whole heavenly host in both courtyards of the Lord's temple.
He passed his sons through the fire in the Valley of Hinnom. He practiced witchcraft, divination, and sorcery, and consulted mediums and spiritists. He did a great deal of evil in the Lord's sight, provoking Him.
References for 2 Chronicles 33:6
Manasseh set up a carved image of the idol he had made, in God's temple, about which God had said to David and his son Solomon: "I will establish My name forever in this temple and in Jerusalem, which I have chosen out of all the tribes of Israel.
References for 2 Chronicles 33:7
I will never again remove the feet of the Israelites from upon the land where I stationed your ancestors, if only they will be careful to do all that I have commanded them through Moses-all the law, statutes, and judgments."
References for 2 Chronicles 33:8
So Manasseh caused Judah and the inhabitants of Jerusalem to stray so that they did worse evil than the nations the Lord had destroyed before the Israelites.
References for 2 Chronicles 33:9