premise: Sennacherib's youngest daughter was Esarhaddon.
hypothesis: Esarhaddon . He was the youngest son of Sennacherib and the West Semitic queen Naqi'a ( Zakitu ) , Sennacherib 's second wife . Sennacherib . He was assassinated in obscure circumstances in 681 BCE , apparently by his eldest son ( his designated successor , Esarhaddon , was the youngest ) .