When hostilities flared up once more with Mitanni, Tulipinu, Suppiluliuma's son and viceroy at Aleppo invaded Carchemish but was unable to take the city. Suppiluliuma met with his son and then invaded Syria himself, laying siege to the city of Carchemish. Suppiluliuma broke the siege on the eighth day, installing his son Piyassili as viceroy of the kingdom. With his sons as viceroys of Aleppo and Carchemish, Suppiluliuma had cemented his rule over Syria and brought the empire of Mitanni to an end. The Mitanni King was assassinated soon after.