The Sun god of Heaven (Hittite: nepišaš Ištanu[1]) was a Hittite solar deity. He was the second-most worshipped solar deity of the Hittites, after the Sun goddess of Arinna.[2] The Sun god of Heaven was identified with the Hurrian solar deity, Šimige.[3]
From the time of Tudḫaliya III, the Sun god of Heaven was the protector of the Hittite king, indicated by a winged solar disc on the royal seals, and was the god of the kingdom par excellence.[4] From the time of Suppiluliuma I (and probably earlier), the Sun god of Heaven played an important role as the foremost oath god in interstate treaties.[5]
As a result of the influence of the Mesopotamian Sun god Šamaš, the Sun god of Heaven also gained an important role as the god of law, legality, and truth.[6]