The Georgian Kingdom of Kartli-Kakheti, part of which was the major territory of modern South Ossetia, was annexed by the Russian Empire in 1801. Following the Russian Revolution, the area of modern South Ossetia was an integral part of the Menshevik Georgian Democratic Republic. A series of Ossetian rebellions took place between 1918 and 1920 during which Ossetians attempted to establish Soviet rule under the Bolsheviks.
The Soviet Georgian government established created the South Ossetian Autonomous Oblast in April 1922. Although the Ossetians had their own language (Ossetian), Russian and Georgian were administrative/state languages. In 1989, two-thirds of Ossetians in the Georgian SSR lived outside South Ossetia.
South Ossetians declared independence from Georgia in 1990, calling themselves the Republic of South Ossetia. The Georgian government responded by abolishing South Ossetia's autonomy and trying to re-establish its control over the region by force. The crisis escalation led to the 1991–92 South Ossetia War, when Georgian troops entered Tskhinvali. The fighting was characterised by general disregard for international humanitarian law by uncontrollable militias, with both sides reporting atrocities. As a result of the war, approximately 1,000 died and about 100,000 ethnic Ossetians fled the territory and Georgia proper, most across the border into North Ossetia.
Since June 2004, serious tensions began to rise as the Georgian authorities strengthened their efforts to bring the region back under their rule, by establishing an alternative pro-Georgian government for South Ossetia in Tbilisi. Georgia also sent police to close down a black market, which was one of the region's chief sources of revenue, selling foodstuffs and fuel smuggled from Russia. This led to fighting by Georgian troops and peacekeepers against South Ossetian militiamen and freelance fighters from Russia.
The Georgian government protested against the allegedly increasing Russian economic and political presence in the region and against the uncontrolled military of the South Ossetian side.
Tensions between Georgia and Russia began escalating in April 2008. In five days of fighting, the Russian forces captured Tskhinvali, pushed back Georgian troops, and largely destroyed Georgia’s military infrastructure using airstrikes deep inside the Georgia proper.
Through mediation by President of France Nicolas Sarkozy, the parties reached a ceasefire agreement on 12 August. On 17 August, Dmitry Medvedev announced that Russian forces were to begin withdrawal on the next day. On 8 October, Russian forces withdrew from the buffer zones adjacent to Abkhazia and South Ossetia. The control of the buffer zones was handed over to the EU monitoring mission in Georgia.
Russia recognised Abkhazia and South Ossetia on 26 August. In response, the Georgian government cut diplomatic relations with Russia. Since the war, Georgia has maintained that Abkhazia and South Ossetia are under Russian occupation and remain, legally, part of Georgia.
South Ossetia, Transnistria, Nagorno-Karabakh, and Abkhazia are post-Soviet "frozen conflict" zones. These four unrecognized states maintain friendly relations with each other and form the Community for Democracy and Rights of Nations.