Greek War of Independence
Also called: Battle of Navarino
A war in which the Greeks rose against Ottoman rule. With intervention by Britain, France and Russia, Greece won recognition of its independence in 1830 — the first crack in the Vienna system.

Eugène Delacroix · Public domain · Source
In 1821 the Greeks rose against the Ottoman Empire. Early in the revolt Greek forces massacred Muslim and Jewish inhabitants at Tripolitsa and elsewhere, and the Ottomans called in the army of Muhammad Ali of Egypt to crush the revolt, and news of the massacre on Chios (1822) spread across Europe. Admirers of ancient Greek civilization rallied to the cause — the poet Byron died of illness at Missolonghi while fighting as a volunteer, and Delacroix painted The Massacre at Chios.
Weighing their own interests, Britain, France and Russia destroyed the Ottoman–Egyptian fleet at Navarino in 1827. The London Protocol of 1830 recognized Greek independence, and Greece became a kingdom in 1832. The very powers that upheld the Vienna system had backed a national movement, cracking the system, and the “Eastern Question” over the decline of the Ottoman Empire came to the fore.