Aššur-nādin-aḫḫē I, son of Aššur-rabi I [http://oracc.museum.upenn.edu/riao/fromsamsiaddutomittanicilent18081364bc/mittanianhegemony/ashurrabii/index.html] was the sixty-sixth ruler of Assyria, according to the Assyrian King List [http://oracc.museum.upenn.edu/riao/kinglists/assyriankinglist/assyriankinglist/index.html#Mittani] (AKL). Unfortunately, the length of his reign is not known as it is either damaged or missing in the extant copies of the AKL (Nassouhi [http://oracc.museum.upenn.edu/riao/kinglists/assyriankinglist/nassouhilist/index.html], Khorsabad [http://oracc.museum.upenn.edu/riao/kinglists/assyriankinglist/khorsabadlist/index.html], and SDAS [http://oracc.museum.upenn.edu/riao/kinglists/assyriankinglist/sdaslist/index.html]), which records that his brother Enlil-nāṣir II [http://oracc.museum.upenn.edu/riao/fromsamsiaddutomittanicilent18081364bc/mittanianhegemony/enlilnasirii/index.html] deposed him.
Two fragmentary inscriptions are written in the name of a Aššur-nādin-aḫḫē, but it is uncertain whether these should be ascribed to the first or second Assyrian king of that name; scholars generally assign them to Aššur-nādin-aḫḫē II [http://oracc.museum.upenn.edu/riao/fromsamsiaddutomittanicilent18081364bc/mittanianhegemony/ashurnadinahheii/index.html] (Grayson, RIMA 1, p. 105). There is a slight possibility that Aššur-nādin-aḫḫē I is referred to in a letter of Assur-uballiṭ I from El Amarna (Rainey 2015:130 letter 16) where an Aššur-nādin-aḫḫē is credited with initiating diplomatic relations with Egypt (Kühne 1973:77-78 n.387). This may have been difficult since Assyria would have been a vassal of Mittani at that time.
Yehonatan Hershkovitz
Yehonatan Hershkovitz, 'Aššur-nādin-aḫḫē I', The Royal Inscriptions of Assyria online (RIAo) Project, The RIAo Project, a sub-project of MOCCI, 2022 [http://oracc.museum.upenn.edu/riao/fromsamsiaddutomittanicilent18081364bc/mittanianhegemony/ashurnadinahhei/]