A copy of a treaty has been recovered between him and Alaksandu, ruler of Wilusa (Troy), one of the Arzawa lands.
Egyptologists suspect that Muwattalli reached an informal peace treaty or understanding with Seti I over Kadesh to avoid a clash between the two superpowers over control of Syria. In it, Seti I effectively ceded Kadesh to the Hittite king in order to focus on domestic issues in Egypt.
Muwatalli had at least two children, both given Hurrian names in honor of the Hurrian storm god Teshup. One was Urhi-Teshup, who became king Mursili III until Hattusili III deposed him. Another was Ulmi-Teshup, who became the vassal ruler of Tarhuntassa.
Muwatalli's namesake, Muwatalli I, was a pre-Empire king of the early 14th century, the predecessor of Tudhaliya I.
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