What was known by contemporaries as the "second" Russo-Turkish war started due to the Turks' dissatisfaction with Russian gains, which were the result of the "first" Russo-Turkish war of 1768 - 1774. During the first war, the Russians had taken Moldavia, Valakhia and Crimea, and cut off the strait of Dardanella. The Turkish army had to regain these lands and to prepare a bridgehead for the further invasion of Europe. The Austrians were allied to Russia in this war. The Turks knew that Russia was unprepared for war, and counted on a quick victory. In the autumn of 1787, Turkish vessels approached Kynburn, a fortress at the mouth of the Dnieper river, and began a siege. The Russian fleet consisted of small ships and could not hinder the Turkish landing forces. The Russian troops were under the command of A. V. Suvorov, who managed to effectively organize the defence of the fortress and, having repulsed the Turkish attacks, turned their army to flight. In the course of this war, the allied Russia and Austria gained a number of other victories. In 1789, Potjemkin successfully assaulted Ochakov. Ushakov sank the Turkish fleet at Feedonisi island. In 1789, the Turks were defeated at Fokshany and Rimnik, and in 1790 Suvorov took Ismail. The war ended on December 22nd, 1791, in the Yassen truce, through which the Turks recognized the Russian achievements.