(c. 647-609 BC) King of Judah. Grandson of Manasseh and son of Amon, he succeeded to the throne at the age of eight. The discovery of a Book of Instruction (probably Deuteronomy, a book of the Old Testament) during repairs of the Temple 621 BC stimulated thorough reform, which included the removal of all sanctuaries except that of Jerusalem. He was killed in a clash at Megiddo with Pharaoh-nechoh, king of Egypt.