The Greek War of Independence, also known as the Greek Revolution or the Greek Revolution of 1821, was a successful war of independence by Greek revolutionaries against the Ottoman Empire between 1821 and 1829. In 1826, the Greeks were assisted by the British Empire, Kingdom of France, and the Russian Empire, while the Ottomans were aided by their North African vassals, particularly the eyalet of Egypt. The war led to the formation of modern Greece, which would be expanded to its modern size in later years. The revolution is celebrated by Greeks around the world as independence day on 25 March every year.
All Greek territory, except the Ionian Islands, the Mani Peninsula and some mountainous regions in Epirus came under Ottoman rule in the 15th century, in the decades surrounding the Fall of Constantinople. During the following centuries, there were many Greek uprisings against Ottoman rule. Most of these uprisings began in the independent Greek realm of the Mani Peninsula which was never conquered by the Ottomans, with the largest war culminating in 1770 during the Orlov Revolt. In 1814, a secret organization called the Filiki Eteria (Society of Friends) was founded with the aim of liberating Greece, encouraged by revolution, which was common in Europe at the time. The Filiki Eteria planned to launch revolts in the Peloponnese, the Danubian Principalities and Constantinople. The insurrection was planned for 25 March 1821 (in the Julian Calendar), the Orthodox Christian Feast of the Annunciation. However, the plans of the Filiki Eteria were discovered by the Ottoman authorities, forcing the revolution to start earlier. The first revolt began on 21 February 1821 in the Danubian Principalities, but it was soon put down by the Ottomans. These events urged Greeks in the Peloponnese (Morea) into action and on 17 March 1821, the Maniots were first to declare war. In September 1821, the Greeks, under the leadership of Theodoros Kolokotronis, captured Tripolitsa. Revolts in Crete, Macedonia, and Central Greece broke out, but were eventually suppressed.