In 1807 war again broke out between Russia and Turkey, but after the Peace of Tilsit (June 1807) fighting ceased also between the Turks and the Russians and the Serbs, not before the Russians had won several successes against the Turks on the Lower Danube. It was during the two following years of peace that dissensions first broke out amongst the Serbian leaders; fighting the Turks was the sole condition of existence which prevented them fighting each other. In 1809-10 Russia and the Serbs again fought the Turks, at first without success, but later with better fortune. In 1811 Kara-George was elected _Gospodar_, or sovereign, by a popular assembly, but Serbia still remained a Turkish province. At the end of that year the Russians completely defeated the Turks at Rustchuk in Bulgaria, and, if all had gone well, Serbia might there and then have achieved complete independence. But Napoleon was already preparing his invasion and Russia had to conclude peace with Turkey in a hurry, which necessarily implied that the Sultan obtained unduly favourable terms. In the Treaty of Bucarest between the two countries signed in May 1812, the Serbs were indeed mentioned, and promised vague internal autonomy and a general amnesty, but all the fortified towns they had captured were to be returned to the Turks, and the few Russian troops who had been helping the Serbs in Serbia had to withdraw. Negotiations between the Turks and the Serbs for the regulation of their position were continued throughout 1812, but finally the Turks refused all their claims and conditions and, seeing the European powers preoccupied with their own affairs, invaded the country from Bosnia in the west, and also from the east and south, in August 1813. The Serbs, left entirely to their own resources, succumbed before the superior forces of the Turks, and by the beginning of October the latter were again masters of the whole country and in possession of Belgrade. Meanwhile Kara-George, broken in health and unable to cope with the difficulties of the situation, which demanded successful strategy both against the overwhelming forces of the Turks in the field and against the intrigues of his enemies at home, somewhat ignominiously fled across the river to Semlin in Hungary, and was duly incarcerated by the Austrian authorities.