2 Chronicles 33:1, 12, 19

Manasseh was twelve years old when he began to reign, and he reigned fifty and five years in Jerusalem

And when he was in affliction, he besought the LORD his God, and humbled himself greatly before the God of his fathers

His prayer also, and how God was intreated of him, and all his sins, and his trespass, and the places wherein he built high places, and set up groves and graven images, before he was humbled: behold, they are written among the sayings of the seers.