The modern history of the Crimea begins with the defeat of the Ottoman Empire by Catherine the Great in 1783 and the handing over of the Crimea by the Ottoman Empire to Russia as part of the Treaty provision. After two centuries of conflict, the Russian fleet had destroyed the Ottoman navy and the Russian army had inflicted heavy defeats on the Ottoman land forces. The ensuing Treaty of Küçük Kaynarca forced the Sublime Porte to recognize the Tatars of the Crimea as politically independent. Catherine the Great's incorporation of the Crimea in 1783 from the defeated Ottoman Empire into the Russian Empire increased Russia's power in the Black Sea area. The Crimea was the first Muslim territory to slip from the sultan's suzerainty. The Ottoman Empire's frontiers would gradually shrink for another two centuries, and Russia would proceed to push her frontier westwards to the Dniester.
In 1921 the Crimean Autonomous Soviet Socialist Republic was created. This republic was dissolved in 1945, and the Crimea became an oblast first of the Russian SSR (1945–1954) and then the Ukrainian SSR (1954–1991). Since 1991 the territory was covered by the Autonomous Republic of Crimea and Sevastopol City within independent Ukraine . During the 2014 Crimean crisis , the peninsula was taken over by pro-Russian forces and a referendum on whether to join Russia was held. Shortly after the result in favour of joining Russia was announced, Crimea was annexed by the Russian Federation as two federal subjects : the Republic of Crimea and the federal city of Sevastopol .