As the Ottoman Empire steadily weakened during the 19th century , Russia stood poised to take advantage by expanding south . In the 1850s , the British and the French , who were allied with the Ottoman Empire , were determined not to allow this to happen . A. J. P. Taylor argues that the war resulted not from aggression but from the interacting fears of the major players : In the early 1800s , the Ottoman Empire suffered a number of setbacks which challenged the existence of the country . The Serbian Revolution in 1804 resulted in the self-liberation of the first Balkan Christian nation under the Ottoman Empire . The Greek War of Independence , which began in early 1821 , provided further evidence of the internal and military weakness of the Ottoman Empire , and the commission of atrocities by Ottoman military forces ( see Chios massacre ) also undermined the Ottomans . The disbandment of the centuries-old Janissary corps by Sultan Mahmud II on 15 June 1826 ( Auspicious Incident ) helped the Ottoman Empire in the longer term , but in the short term it deprived the country of its existing standing army . In 1828 , the allied Anglo-Franco-Russian fleet destroyed almost all the Ottoman naval forces during the Battle of Navarino . In 1830 , Greece became an independent state after 10 years of war and the Russo-Turkish War ( 1828 – 29 ) . According to the 1829 Treaty of Adrianople , Russian and Western European commercial ships were authorized to freely pass through the Black Sea straits , Serbia received autonomy , and the Danubian Principalities ( Moldavia and Wallachia ) became territories under Russian protection
Chios massacre
Chios massacre
Crimean War