border, entered Isuwa and returned the fugitives (or deserters or exile governments) to Hittite rule. "I freed the lands which I captured; they dwelt in their places. All the people whom I released rejoined their peoples and Hatti incorporated their territories," Suppiluliuma later boasted. The Hittite army then marched through various districts towards the Mitanni capital of Washshukanni. Suppiluliuma claims to have plundered the district and to have brought loot, captives, cattle, sheep and horses back to Hatti. He also claims that Tushratta fled, but obviously he failed to capture the capital. While the campaign weakened Tushratta's kingdom, he still held onto his throne. A second campaign In a second campaign, the Hittites again crossed the Euphrates and subdued Halab, Mukish, Niya, Arahati, Apina, and Qatna as well as some cities whose names have not been preserved. Charioteers are mentioned among the booty from Arahati, who were brought to Hatti together with all their possessions. While it was common practice to incorporate enemy soldiers in the army, this might point to a Hittite attempt to counter the most potent weapon of the Mitanni, the war-chariots, by building up or strengthening their own chariot forces. Tushratta had possibly suspected Hittite intentions on his kingdom, for the Amarna letters include several tablets from Tushratta concerning the marriage of his daughter Tadukhipa with Akhenaten, explicitly to solidify an alliance with the Egyptian kingdom. However, when Suppiluliuma invaded his kingdom, the Egyptians failed to respond in time—perhaps because of the sudden death of Akhenaten, and the resulting struggle for control of the Egyptian throne. According to a treaty later made between Suppiluliuma and Shattiwaza, a son of Tushratta, after a third devastating Hittite raid led to the fall of Carchemish, Tushratta was assassinated by a group led by one of his sons. A time of civil war followed which came to an end when Suppiluliuma placed Shattiwaza on the Mitannian throne. Amarna letters Six of the Tushratta letters, including EA 24, were subjected to Neutron Activation Analysis to match the clay composition to potential sites for Waššukanni. The results ruled out a Tell Fakhariyah location. From King Tushratta to Amenhotep III Amarna letter EA 17, Amarna letter EA 18, Amarna letter EA 19, "Love and Gold" Amarna letter EA 20, Amarna letter EA 21, Amarna letter EA 22, "Presents from Tushratta to Amenhotep III, when he gave to him his daughter Tadukhipa to wife"