Greece played a peripheral role in the war. When Russia attacked the Ottoman Empire in 1853, King Otto of Greece saw an opportunity to expand North and South into Ottoman areas that had large Greek Christian majorities. However, Greece did not coordinate its plans with Russia, did not declare war, and received no outside military or financial support. Greece, an Orthodox nation, had considerable support in Russia, but the Russian government decided it was too dangerous to help Greece expand its holdings.:32–40 When the Russians invaded the Principalities, the Ottoman forces were tied down so 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, and effectively neutralized the Greek army. Greeks, gambling on a Russian victory, incited the large-scale Epirus Revolt of 1854 as well as uprisings in Crete. The insurrections were failures that were easily crushed by the Ottoman army. Greece was not invited to the peace conference and made no gains out of the war.:139 The frustrated Greek leadership blamed the King for failing to take advantage of the situation; his popularity plunged and he was later forced to abdicate.

When Russia attacked the Ottoman Empire who glimpsed an opportunity to advance North and South?