Esarhaddon, (?-669 B.C.), a king of ancient Assyria. The Assyrian empire reached its height under his rule. He became king in 681 B.C. after his father Sennacherib was killed. Esarhaddon defeated his brothers and put down a revolt in Babylonia. He overran Palestine, subdued Judah, and conquered Egypt. He died while on his way to put down an Egyptian revolt. Esarhaddon did much building in Nineveh and Babylon.