In 1821, the Greeks rose up against the Ottoman Empire. Initial successes were followed by infighting, which almost caused the Greek struggle to collapse; nevertheless, the prolongation of the fight forced the Great Powers (Britain, Russia and France) to recognize the claims of the Greek rebels to separate statehood (Treaty of London) and intervene against the Ottomans at the Battle of Navarino. Greece was initially to be an autonomous state under Ottoman suzerainty, but by 1832, in the Treaty of Constantinople, it was recognized as a fully independent kingdom. In the meantime, the 3rd National Assembly of the Greek insurgents called upon Ioannis Kapodistrias, a former foreign minister of Russia, to take over the governance of the fledgling state in 1827.