His reign also marked the first breakaway from the Ottoman Empire, with Greece gaining its independence following a revolution that started in 1821. During the Battle of Erzurum (1821), part of the Ottoman-Persian War (1821-1823), Mahmud II's superior force was routed by Abbas Mirza, resulting in a Qajar Persian victory which got confirmed in the Treaties of Erzurum. Several years later, in 1827, the combined British, French and Russian navies defeated the Ottoman Navy at the Battle of Navarino; in the aftermath, the Ottoman Empire was forced to recognize Greece with the Treaty of Constantinople in July 1832. This event, together with the French conquest of Algeria, an Ottoman province (see Ottoman Algeria) in 1830, marked the beginning of the gradual break-up of the Ottoman Empire. Non-Turkish ethnic groups living in the empire's territories, especially in Europe, started their own independence movements.