the younger Esarhaddon; in Sennacherib's case this decision led to Arda-Mulissu murdering him and fighting a civil war against Esarhaddon. Why Esarhaddon made nearly the same decision is not clear. Promoting one of his sons as the heir to Assyria and another as the heir to Babylon was a novel idea; for the past decades the Assyrian king had simultaneously been the king of Babylon. The decision to leave Babylonia to Shamash-shum-ukin and to designate the two as "equal brothers" might have been intended to counteract the possible damage inherit in designating Ashurbanipal as the sole heir, avoiding future jealousy and rivalry. One hypothesis in regard to why a younger son was designated as the heir to what was clearly Esarhaddon's primary title is that Ashurbanipal and Shamash-shum-ukin could have had different mothers. Though it is equally likely that Shamash-shum-ukin and Ashurbanipal shared a mother, possibly Esharra-hammat (Esarhaddon's primary consort), it is also possible that Ashurbanipal was the son of an Assyrian woman and Shamash-shum-ukin was the son of a Babylonian woman; Shamash-shum-ukin accceding to the Assyrian throne could thus have been problematic. After Esarhaddon made his decision, the two princes arrived at the Assyrian capital of Nineveh together and partook in a celebration in May 672 with foreign representatives, Assyrian nobles and elements of the military. Since the name Ashurbanipal (Aššur-bāni-apli) means "Ashur is the creator of the heir", it was likely granted to him at this time; what name Ashurbanipal used before he became crown prince is not known. It was also perhaps around this time that Ashurbanipal married his future queen, Libbali-sharrat. Crown prince and accession After he was designated as crown prince, Ashurbanipal entered what the Assyrians called the "House of Succession", the palace of the crown prince. As crown prince, Ashurbanipal began to undergo training for traditional royal duties. Among the various skills Ashurbanipal was trained in during this time were hunting, riding, scholarship and wisdom, archery, chariotry and other forms of military training. Because Esarhaddon was constantly ill, much of the administrative duties of the empire fell upon Ashurbanipal and Shamash-shum-ukin during the last few years of their father's reign. It was important for the crown princes to gain real experience in ruling. Letters of correspondence between Esarhaddon and Ashurbanipal from this time show that Ashurbanipal prominently participated in the Assyrian intelligence network, gathering information on foreign enemies and rivals and compiling reports for