Shamash-shum-ukin in the context of "Shamash"

Ashurbanipal (Neo-Assyrian Akkadian: 𒀸𒋩𒆕𒀀, romanized: Aššur-bāni-apli, meaning "Ashur is the creator of the heir") was the king of the Neo-Assyrian Empire from 669 BC to his death in 631. He is generally remembered as the last great king of Assyria. Ashurbanipal inherited the throne as the favored heir of his father Esarhaddon; his 38-year reign was among the longest of any Assyrian king. Though sometimes regarded as the apogee of ancient Assyria, his reign also marked the last time Assyrian armies waged war throughout the ancient Near East and the beginning of the end of Assyrian dominion over the region.

Esarhaddon selected Ashurbanipal as heir c. 673. The selection of Ashurbanipal bypassed the elder son Shamash-shum-ukin. Perhaps in order to avoid future rivalry, Esarhaddon designated Shamash-shum-ukin as the heir to Babylonia. The two brothers jointly ascended to their respective thrones after Esarhaddon's death in 669, though Shamash-shum-ukin was relegated to being Ashurbanipal's closely monitored vassal. Much of the early years of Ashurbanipal's reign was spent fighting rebellions in Egypt, which had been conquered by his father. The most extensive campaigns of Ashurbanipal were those directed towards Elam, an ancient enemy of Assyria, and against Shamash-shum-ukin, who gradually began to resent the overbearing control that his younger brother held over him. Elam was defeated in a series of conflicts in 665, 653 and 647–646. Shamash-shum-ukin rebelled in 652 and assembled a coalition of Assyria's enemies but was defeated and died during Ashurbanipal's siege of Babylon in 648. On account of a lack of surviving records, much of Ashurbanipal's late reign is poorly known.

Nebuchadnezzar (Babylonian cuneiform: Nabû-kudurri-uṣur, meaning "Nabu, watch over my heir"), also spelled Nebuchadrezzar, and most commonly known under the nickname Kudurru, was a governor of the city Uruk in Babylonia under the rule of Ashurbanipal (r. 669–631 BC) of the Neo-Assyrian Empire, appointed after the defeat of Shamash-shum-ukin of Babylon, Ashurbanipal's brother who had rebelled against Assyria, c.  648 BC. He was likely the son of the high priest Nabonassar.

In the reign of Ashurbanipal's son Sinsharishkun (r. 627–612 BC), the grave of Nebuchadnezzar was desecrated, with the perpetrators going so far as dragging his body through the streets of Uruk. This was done as a response to the anti-Assyrian activities of his two sons. In 2007, Assyriologist Michael Jursa identified Nebuchadnezzar as the father of Nabopolassar, the founder of the Neo-Babylonian Empire, who rebelled against Sinsharishkun in 626 BC (this being the anti-Assyrian activities). If Nabopolassar was his son, Nabopolassar would go on to name his own son, Nebuchadnezzar II, after his father.