The Greek War of Independence, also known as the Greek Revolution, is  a successful war of independence waged by Greek revolutionaries against the Ottoman Empire between 1821 and 1830.

The Greeks were later assisted by the Russian Empire, Great Britain, the Kingdom of France, while the Ottomans were aided by their North African vassals, the eyalets of Egypt, Algeria, and Tripolitania, and the Beylik of Tunis.

Even several decades before the fall of Constantinople to the Ottoman Empire in 1453, most of Greece had come under Ottoman rule.

During this time, there were several revolt attempts by Greeks to gain independence from Ottoman control.

In 1814, a secret organization called the Filiki Eteria (Friendly Brotherhood) was founded with the aim of liberating Greece.

The Filiki Eteria planned to launch revolts in the Peloponnese, the Danubian Principalities, and in Constantinople and its surrounding areas.

By late 1821, the insurrection had been planned for March 25 (Julian Calendar) 1821, on the Feast of the Annunciation for the Orthodox Christians.

However, as the plans of Filiki Eteria had been discovered by the Ottoman authorities, the revolutionary action starts earlier.

The first of these revolts begins on March 6/February 22, 1821 in the Danubian Principalities, but it is soon put down by the Ottomans.

The events in the north urge the Greeks in the Peloponnese into action and on March 17, 1821, the Maniots declare war on the Ottomans.

This declaration is the start of a spring of revolutionary actions from other controlled states against the Ottoman Empire.

On March 25 the revolution is officially declared and by the end of the month, the Peloponnese is in open revolt against the Turks.

By October 1821, the Greeks under Theodoros Kolokotronis have captured Tripolitsa.

The Peloponnesian revolt is quickly followed by revolts in Crete, Macedonia, and Central Greece, which will soon be suppressed.

Meanwhile, the makeshift Greek navy is achieving success against the Ottoman navy in the Aegean Sea and prevent Ottoman reinforcements from arriving by sea.

Tensions soon develop among different Greek factions, leading to two consecutive civil wars

In the meantime, the Ottoman Sultan negotiates with Mehmet Ali of Egypt, who agrees to send his son Ibrahim Pasha to Greece with an army to suppress the revolt in return for territorial gain.

Ibrahim lands in the Peloponnese in February 1825 and has immediate success: by the end of 1825, most of the Peloponnese is under Egyptian control, and the city of Missolonghi falls in April 1826 after a year-long siege by the Turks.

Although Ibrahim is defeated in Mani, he has succeeded in suppressing most of the revolt in the Peloponnese, and Athens has been retaken.

Following years of negotiation, three Great Powers—Russia, Britain and France—decide  to intervene in the conflict and each nation sends a navy to Greece.

Following news that combined Ottoman–Egyptian fleets are going to attack the Greek island of Hydra, the allied fleet intercepts the Ottoman–Egyptian fleet at Navarino.

The battle begins after a tense week-long standoff, ending in the destruction of the Ottoman–Egyptian fleet.

By 1828 the Egyptian army withdraws under pressure of a French expeditionary force to which the Ottoman garrisons in the Peloponnese then surrender, while the Greeks proceed to the Ottoman-controlled part of central Greece

After eight years of war, Greece is finally recognized as an independent, sovereign state under the London Protocol of February 1830.

Later, in 1832, the London Conference and the Treaty of Constantinople define  the final borders of the new state and establish prince Otto of Bavaria as the first king of Greece.

The Greek Revolution is celebrated by the modern Greek state as a national day on March 25.