The Greeks had never been fully disarmed. The Klephtes (Klephts) at that time were a large number of patriots or volunteers (outlaws for the Turks) that had become large bands of armed brigands living in the rough mountainous regions or other remote areas throughout Greece, and the Armatoli (the gendarmerie) of whom most had become Klephts, all of them increasingly more daring. Most of their Kapetanaioi (captains or commanders) had also been sworn into the Philiki Etairia. Among them were Theodoros Kolokotronis, Markos Botsaris, Athanasios Diakos, Papaflessas, Makriyannis and other. They were organized and armed by the Hetairia. Others ready to serve the cause were admirals Andreas Miaoulis and Konstantinos Kanaris who were to command ships furnished mainly by the wealthy islanders of Spetsai, Hydra and Psara.

The Philiki Etairia had given the leadership of the revolution to Prince Alexandros Ypsilantis, a Greek Phanariote from the Danubian provinces who had become a general in the Russian army and aide-all-camp to the Tsar.

The time had come at last when the Greeks who were living in foreign countries (Diaspora) had to move forward. Early in March 1821, it was decided for Alexander Ypsilantis with 4500 volunteers, Greek officers and 700 Greek students assembled at Jassy in Moldavia, near the Russian border, to begin the insurrection against the Ottoman rule starting in the Danubian principalities. Unfortunately they were inexperienced in warfare, poorly organized and not sufficiently armed, and the Vlach and Greek population did not rise as was expected. The Turks, expecting large uprisings, had sent strong army and the volunteers were massacred.

When the revolt under Alexander Ypsilantis became known in Constantinople and spies reported the unrest in the Peloponnese, the Sultan ordered the arrest of the Greek Orthodox Patriarch Gregory V as the ethnic leader of the Greeks, capturing as well two metropolitans and twelve bishops and the leading Phanariotes. Shortly after they were all hung and many other Greeks, clerics and laity were killed by the Turks in a wild bloodbath.

The leaders and their men swore "Liberty or Death" which became the slogan in all of the fierce battles that followed. The Garrison town of Kalamata was the first to fall to the Maniates. In April 1821, battles broke out everywhere. In October 1821 the fortified capital of Tripolitsa fell to the Kolocotronis army and most of the Peloponnese soon became free. The Greeks now began extermination of the Turks, and at least 10,000 Turks lost their lives during the first weeks of war.

Early in 1822, in a particularly violent act of vengeance, the Turks, invaded the Island of Chios, in the eastern Aegean and slaughtered about 25,000 Chiotes. They took another 50,000 as slaves out of a total population of about 100,000.

The Greeks, determined to gain their independence fought with suicidal courage despite meager resources. The Turks were equally determined to put down the revolt. The struggle was to last without relief for eight years. However, it was not possible for the strong-minded Greek Leaders who contributed greatly to the war effort to cooperate with each other to create a nation. There was little experience in statemanship and public administration, and no past history of a Greek nation upon which to draw. At this time, key figures included the fierce Klepht captains accustomed to their aristocratic ways. Also involved were a number of eminent Phanariotes who joined the cause. Also prominent landowners and the islanders had their own cores of strength and political prejudices. The Greek Orthodox Church leaders were also participating and had their own strong views as well. These divergent and parochial antagonisms ended up in civil war, and some important leaders retired in disgust, although the Ottoman enemy was still to be defeated.

By the end of 1824 the Peloponnese had been virtually liberated and the various factions tried to form a constitution and a Central Greek Government, but with no real success. Meanwhile, Sultan Mahmod II asked Mehmet Ali, Turkish Pasha of Egypt to intervene with his powerful land and sea forces. The price for this involvement was high. Mehmet Ali was to receive Pashalik of Crete immediately.

If his forces won, he would also be given the Pashalik of Syria for himself and for his able son Ibrahim Pasha who would lead the forces all of the Morea (Peloponnese).

In February 1825, the Egyptians landed a large invasion force at Methoni, in the south west corner of the Peloponnese, one of the few ports remaining in Turkish control. The progress of the invading Muslim forces was rapid and devastating, and within a year most of the Peloponnese was retaken by them. Mesolongi also fell in April 1826 after a very long siege, in punishment for which the Muslims massacred 10,000 of 12,000 inhabitants (of which only 3,000 had been combatants). Athens fell in August 1826.

For some time, it had been obvious that, however bravely the Greeks fought for Greece's independence, aided by the Philhellenes, their own factionalism and the superior Muslim forces could not be overcome without additional help from the Great Powers of Europe. Of these England, France and Russia were the principal countries with interests in the area. While they were generally sympathetic towards the Greeks, they were by no means entirely against Turks. On July 6, 1827 the three powers signed a treaty in London to seek mediation with Turkey on behalf of the Greeks, and created a combined naval fleet to enforce the armistice when it came. Ibrahim was asked by the admirals of the Power's fleet that he respect the armistice. For some reason he failed to respond.

On October 20, 1827, the European fleet sailed into Navarino Bay to confront the Turkish-Egyptian fleet anchored in a semi-circle. Someone on an Egyptian vessel fired on a small boat from an English warship whose occupants were sent to parley with them. General cannon fire immediately broke out. At the end of the shooting two thirds of the Muslim vessels had been sunk or were sinking and many thousand of sailors were killed. The Powers suffered damage but no vessels were sunk and fewer than 200 of their men were killed.

After the Navarino Battle and after maneuverings by the Great Powers there was declaration of war against Turkey by Russia. The Sultan, after 8 and a half years of revolution, recognized Greece as an independent nation with full diplomatic status. Yet only one part of the mainland and a few islands were freed. It took other wars to maintain the free status that Greece enjoys today.