His place in the sequence of Babylonian rulers is confirmed by an
Assyrian
Synchronistic Kinglist fragment. A contemporary source for information concerning his reign is found in an inscription of the governor of
Borsippa, Nabû-šuma-imbi, which highlights his weakness and the autonomy of his regional officials. This barrel cylinder The coincidental recording of years five and six of a no longer legible ruler in the
Chronicle of the Market Prices has led this reference to be assigned to him. In the king’s eighth year, Nabû-šuma-imbi was able to install a certain Nabû-mutakkil as a temple official He is the main subject of a chronicle, "The
Crimes and Sacrileges of Nabu-šuma-iškun", uncovered in
Uruk in a
Seleucid era dwelling belonging to the exorcist Anu-ikṣur on the
Parthian mound southeast of the Eanna complex, whose underlying theme is his violation of all moral and legal principles and consequentially – his ignominious demise. His crimes included “burn(ing) alive sixteen
Cutheans at Zababa's gate in the heart of Babylon;” “he committed insult and unspeakable slander” of a certain Iltagal-il of the town Dur-ša-Karbi, and “a leek, a thing forbidden in the Ezida, he brought to the temple of Nabû and gave to eat to the one 'entering the temple'(i.e. the priest)," apparently an unforgivable act. Unfortunately the Chronicle was damaged in antiquity so how he met his come-uppance is not preserved. The length of his reign is uncertain, as it is not preserved in chronicle or king list references, but his reign is known to have ended in 748 BC as the chronology is fixed from the reign of
Nabû-Nasir onward, and there is a legal text recording the sale of a plot of land, and a grain receipt dated to his tenth year, and two economic texts to his thirteenth year. ==Inscriptions==