Aq Qoyunlu territory expanded further following their defeat of the Kara Koyunlu in Iran (1467–69), and Uzun Hassan moved his capital to Tabriz. However, Hassan followed up these successes with a disastrous campaign against the Ottoman Empire. Hassan's army of light cavalry was routed by Mehmed II's Ottoman forces, armed with rifles and cannon, at the Battle of Otlukbeli near Erzincan in August 1473. While Uzun Hassan survived, his son Zeynel Bey was killed in battle. In commemoration, the Mausoleum of Zeynel Bey was erected in Hasankeyf in about 1474 on the orders of either Uzun Hassan, or Zeynel's elder brother, Khalil. The shrine is currently moved to a new location to avoid inundation by the rising waters of the nearby dam.