2 Kings 22:1

Josiah was eight years old when he began to reign, and he reigned thirty and one years in Jerusalem. And his mother's name was Jedidah, the daughter of Adaiah of Boscath.

Josiah was eight years old when he began to reign. Happier than his grandfather Manasseh, he seems to have fallen, during his minority, under the care of better guardians, who trained him in the principles and practice of piety; and so strongly had his young affections been enlisted on the side of true and undefiled religion, that he continued to adhere all his life, with undeviating perseverance, to the cause of God and righteousness.