Originally part of the Mitanni Empire, Adad-Nirari engaged in a military struggle against the invading Hittite king Šuppiluliuma I, asking Egypt for help.
[4] Following his second Syrian foray,[note 2] Šuppiluliuma sent an offer of alliance to the Nuhaššite king; Adad-Nirari rejected, and despite being a vassal of Mitanni, he sent the letter codenamed (EA 51) to ask Egypt for help and troops.
[13][14] According to Niqmaddu II, the troops of Adad-Nirari and his allies seized the cities of Ugarit, took booty and devastated the land.
[18] There is a great deal of confusion over the identity of Adad-Nirari as king of Nuhašše and his position in the succession of the Nuhaššite monarchs.
[24] Many scholars dealt with the problem and offered different and contradictory opinions:[18] The inventories of Qatna mentions a king named Adad-Nirari; Michael Astour suggested identifying the Qatanite king with the Nuhaššite monarch and was followed by Richter,[28] who believes that Adad-Nirari ruled Qatna through a šakkanakku (military governor) called Lullu mentioned in the Qatanite inventories.