King Josiah was a ruler of the ancient kingdom of Judah who reigned from approximately 640 to 609 BCE. He became king at a young age and is known for his significant religious reforms. Josiah sought to restore the worship of Yahweh and eliminate pagan practices, which had become prevalent in his kingdom. During his reign, Josiah discovered a book of the law in the Temple of Jerusalem, believed to be part of the Torah. This discovery led him to initiate a major religious revival, including the celebration of the Passover and the renewal of the covenant between Yahweh and the people of Judah.