When the Crimean War broke out in 1854, Greece saw an opportunity to gain Ottoman-controlled territory that had large Greek populations. Greece, an Orthodox nation, had considerable support in Russia, but the Russian government decided it was too dangerous to help Greece expand its holdings. When the Russians attacked the Ottoman forces, Greece invaded Thessaly and Epirus. To block further Greek moves, the British and French occupied the main Greek port at Piraeus from April 1854 to February 1857. The Greeks, gambling on a Russian victory, incited the large-scale Epirus Revolt of 1854 as well as uprisings in Crete. The revolts failed and Greece made no gains during the Crimean War, which Russia lost.