Proper numbering of the Hittite rulers who bore the name Tudhaliya is problematic. There was a Hattian era figure who bore the name Tudhaliya who may or may not have ruled as king. Other reconstructions insert a Tudhaliya directly after Muwatalli I, but before the Tudhaliya discussed here.
Some scholars call Tudhaliya I the first king of the New Kingdom, or Empire. Others give this honor to Suppiluliuma I. Tudhaliya may have been the grandson of the Middle Kingdom ruler Huzziya II. He may have been the direct successor of Muwatalli I, having overthrown him. The exact sequence of succession at the beginning of the New Kingdom is uncertain, however, because of the difficulty of placing Hattusili II. Tudhaliya I's reign includes a period of co-regency with Arnuwanda I, his son-in-law and adopted son.
The most famous event of Tudhaliya's reign was his conquest of the land Assuwa. Assuwa's name is believed by some scholars to be the origin of the modern place name Asia, although this is not beyond dispute. Further, there were many component territories within Assuwa, including the lands Taruisa and Wilusiya, which are now generally accepted to be references to Troy/Ilios, although there is not enough evidence at this time to explain how these two lands came to apply to a single location.
^King (lugal) of Tarhuntassa (Bryce 1997, p. 296); apparently later Great King of Hatti (Bryce 1997, p. 354).
^Nerikkaili married a daughter of Bentesina, king of Amurru (Bryce 1997, p. 294).
^Two daughters of Hattusili III were married to the pharaoh Ramesses II; one was given the Egyptian name Ma(hor)nefrure. Another, Gassuwaliya, married into the royal house of Amurru. Kilushepa was married to a king of Isuwa. A daughter married into the royal family of Babylon. A sister of Tudhaliya IV married Sausgamuwa, king of Amurru after his father Bentesina. From Bryce (1997), pp. 294 and 312.