 Complete the following phrase:  In 1807 Kars successfully resisted an attack by the Russian Empire. During a break between the Russian campaigns in the region conducted against the Ottomans, in 1821, commander-in-chief Abbas Mirza of Qajar Iran occupied Kars, further igniting the Ottoman-Persian War of 1821-1823. After another Russian siege in 1828 the city was surrendered by the Ottomans on June 23, 1828 to the Russian general Count Ivan Paskevich, 11,000 men becoming prisoners of war. At the end of the war it returned to Ottoman control for diplomatic reasons, Russia gaining only two border forts. During the Crimean War an Ottoman garrison led by British officers including General William Fenwick Williams kept the Russians at bay during a protracted siege; but after the garrison had been devastated by cholera and food supplies had depleted, the town was 