Esar-Haddon (ē´sär-hăd´ən), king of ancient Assyria (681–668 BC), son of Sennacherib. Immediately upon ascending the throne he had to put down serious revolts and defeat the Chaldaeans. He was successful in both enterprises. One of the most powerful of the Assyrian kings, Esar-Haddon greatly extended Assyrian conquests. Most important was his conquest (673–670 BC) of Egypt, where, after initial difficulties, he took Memphis. He deposed the defeated Taharka and put Necho in power. Esar-Haddon fought against Elam and was still warring when he died on the way to subdue an Egyptian revolt. He was succeeded by Assurbanipal.