[4] Arnuwanda was declared his father's heir apparent (tuḫkanti) and is attested as such in references to several events taking place during Šuppiluliuma's reign.
Together with his father, mother, and uncle Zida, Arnuwanda was mentioned in the description of the formal installation of his younger brother Telipinu as priest (and governor) of Kizzuwatna.
[8] In 1322 BC, Arnuwanda II seems to have succeeded his father Šuppiluliuma I on the Hittite throne without incident, having long been the recognized heir apparent, and having been entrusted with military command in the conflicts with Mittani and Egypt.
Apparently already ill, Arnuwanda seems to have intended conferring that command to his father's veteran general Ḫannutti, but the latter died soon after meeting with the king.
[11] Fragmentary texts suggest Arnuwanda renewed the treaties of vassalage that his father had concluded with his younger brothers, particularly Piyaššili (Šarri-Kušuḫ) of Carchemish.