Uzun Hasan or Uzun Hassan ( اوزون حسن; ; 1423 – January 6, 1478; where uzun means "tall" in Oghuz Turkic) was a ruler of the Turkoman Aq Qoyunlu state and is generally considered to be its strongest ruler. Hasan ruled between 1452 and 1478, and would preside over the confederation's territorial apex when it included parts or all of present-day Iraq, Turkey, Azerbaijan, Iran, Transcaucasia and Syria. Reign Timur, the founder and ruler of the Timurid Empire, had appointed Uzun Hasan's grandfather, Kara Yülük Osman, as a governor of Diyarbakır, with the cities of Erzincan, Mardin, Ruha (or Urfa), and Sivas. Later, Persia was divided between two Timurid rulers, Jahan Shah of Qara Qoyunlu (the Black Sheep Turkoman) and Uzun Hasan. After twenty years of fighting, Uzun Hasan eventually defeated Jahan Shah in a battle near the sanjak of Çapakçur in present-day eastern Turkey on October 30 (or November 11), 1467. Upon the defeat of the latter, another Timurid ruler, Abu Sa'id Mirza, answered Jahan Shah's son's request for aid, taking much of Jahan Shah's former land and going to war with Uzun Hasan despite the latter's offers of peace. Uzun Hasan then ambushed and captured Abu Sa'id at the Battle of Qarabagh, whereupon he was executed by Yadgar Muhammad Mirza, a rival. In 1463, the Venetian Senate, seeking allies in its war against the Ottomans, sent Lazzaro Querini as its first ambassador to Tabriz, but he was unable to persuade Uzun Hassan to attack the Ottomans. Hassan sent his own envoys to Venice in return. In 1465, Hassan attacked and captured Harput from the Beylik of Dulkadir. In 1471, Querini returned to Venice with Hazzan's ambassador Murad. The Venetian Senate voted to send another to Persia, choosing Caterino Zeno after two other men declined. Zeno, whose wife was the niece of Uzun Hassan's wife, was able to persuade Hassan to attack the Turks. Hassan was successful at first, but there was no simultaneous attack by any of the western powers. Uzun Hasan met the Ottomans in battle near Erzincan in 1471, advanced as far as Akşehir, pillaging and destroying Tokat, and fought a battle at Tercan in 1473. He was defeated by Mehmed II at Battle of Otlukbeli in the late summer of 1473. In 1473, Giosafat Barbaro was selected as another Venetian ambassador to Persia, due to his experience in the Crimean, Muscovy, and Tartary. Although Barbaro