Kalmyk allegiance was often nominal, as the Kalmyk Khans practised self-government, based on a set of laws they called the Great Code of the Nomads (Iki Tsaadzhin Bichig). The Kalmyk Khanate reached its peak of military and political power under Ayuka Khan (ruled 1672–1724, khan 1690–1724). During his era, the Kalmyk Khanate fulfilled its responsibility to protect the southern borders of Russia and conducted many military expeditions against its Turkic-speaking neighbours. Successful military expeditions were also conducted in the Caucasus. The Khanate experienced economic prosperity from free trade with Russian border towns, with China, with Tibet and with Muslim neighbours. During this era, the Kalmyks also kept close contacts with their Oirat kinsmen in Dzungaria, as well as with the Dalai Lama in Tibet. Russian Civil War After the October Revolution in 1917, many Don Kalmyks joined the White Russian army and fought under the command of Generals Denikin and Wrangel during the Russian Civil War. Before the Red Army broke through to the Crimean Peninsula towards the end of 1920, a large group of Kalmyks fled from Russia with the remnants of the defeated White Army to the Black Sea ports of Turkey. The majority of the refugees chose to resettle in Belgrade, Serbia. Other, much smaller, groups chose Sofia (Bulgaria), Prague (Czechoslovakia) and Paris and Lyon (France). The Kalmyk refugees in Belgrade built a Buddhist temple there in 1929. Soviet period In July 1919, Bolshevik leader Vladimir Lenin issued an appeal to the Kalmyk people, calling for them to revolt and to aid the Red Army. Lenin promised to provide the Kalmyks, among other things, a sufficient quantity of land for their own use. The promise came to fruition on November 4, 1920, when a resolution was passed by the All-Russian Central Executive Committee proclaiming the formation of the Kalmyk Autonomous Oblast. Fifteen years later, on October 22, 1935, the Oblast was elevated to republic status, Kalmyk Autonomous Soviet Socialist Republic. In line with the policy of Korenizatsiya based on the concept of titular nations, the government of the Soviet Union adopted a strategy of national delimitation, while at the same time enforcing the Leninist principle of democratic centralism. According to Dorzha Arbakov, decentralized governing bodies were a tool the Bolsheviks used to control the Kalmyk people: After establishing control, the Soviet authorities did not overtly enforce an anti-religion policy, other than through passive means, because it sought