In the power struggle that arose between the Hittites and the Hurrian kingdom of Mitanni, Kizzuwatna became a strategic partner because of its location. Isputahsu made a treaty with Hittite King Telepinu. Later, Kizzuwatna shifted its allegiance, perhaps because of a new ruling dynasty. The city-state of Alalakh, to the south, expanded under its new vigorous leader, Idrimi, himself a subject of the Mitannian king Barattarna. King Pilliya of Kizzuwatna had to sign a treaty with Idrimi. Kizzuwatna became an ally of Mitanni from the reign of Shunashura I to that of Hittite King Arnuwanda I, who overran the country and made it a vassal kingdom. The exceedingly rough and unfavourable terrain of the Tarsus Mountains made it likely that to remain in a position of prominence among their Hurrian- and Luwian- speaking neighbours, the Kizzuwanta requested favourable terms and that they were subsequently granted.