At this time, the Assyrian officials were becoming increasingly powerful relative to the king, and Assyria's enemies were growing more dangerous.
An unusually small share of Ashur-nirari's reign was devoted to campaigns against foreign enemies, perhaps suggesting domestic political instability within Assyria.
In particular, the power of the king himself was being threatened due to the emergence of extraordinarily powerful officials, who, while they accepted the authority of the Assyrian monarch, in practice acted with supreme authority and began to write their own cuneiform inscriptions concerning building and political activities, similar to those of the kings.
[9] It was customary for an Assyrian king to campaign every year which means that Ashur-nirari staying in Assyria could be a sign of domestic instability.
[2][4][11] The nature of Tiglath-Pileser's rise to the throne is not clear, particularly because ancient sources give conflicting accounts of his lineage.
[13] In her 2016 PhD thesis, the historian Tracy Davenport advanced the hypothesis that Tiglath-Pileser may have succeeded entirely legitimately and had even briefly been co-ruler with Ashur-nirari.
Davenport based this idea primarily on oddities in the sequence of eponyms under Tiglath-Pileser, an unusual horizontal line in the list of eponyms after 744 BC (which might mark Ashur-nirari's death) and the Assyrian King List giving Ashur-nirari a reign lasting 10 years.