Russia–United Kingdom relations, also Anglo-Russian relations, are the bilateral relations between Russia and the United Kingdom. Formal ties between the courts started in 1553. Russia and Britain became allies against Napoleon in the early-19th century. They were enemies in the Crimean War of the 1850s, and rivals in the Great Game for control of central Asia in the latter half of the 19th century. They allied again in World Wars I and II, although the Russian Revolution of 1917 strained relations. The two countries were at sword's point during the Cold War (1947–1989). Russia's big business tycoons developed strong ties with London financial institutions in the 1990s after the dissolution of the USSR in 1991.