Shamash-shum-ukin was king of Babylon from 668-648 BC. He was the second son of the Assyrian King Esarhaddon. His elder brother, crown prince Sin-iddina-apla had died in 672, and in his stead the third son Assurbanipal was invested as crown prince and later king of Assyria, while Shamash-shum-ukin remained crown prince of Babylonia. Wikipedia
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