Several minor, unsuccessful and short-lived revolts were conducted against Ottoman rule mostly with the help of the Habsburgs; 1594, 1688–1691, 1718–1739 and 1788. In 1799, the "dahia" (janissary leaders, high-status infantry in the provinces) took over the Sanjak of Smederevo, renouncing the Sultan and imposing higher taxes. In 1804, they murdered the most notable intellectuals and nobles, known as the "Slaughter of the Dukes". In retaliation, the Serbs took arms and had by 1806 killed or driven out all of the "dahia", but the fight did not stop; when the Sultan were to send the new Pasha into the province, the Serbs killed him. The revolt continued, in what would be known as the First Serbian Uprising, with the Serbs under Karageorge defeating the Turks in several battles, liberating most of central Serbia; a fully working government was established. In 1813, Serbs suffered a huge defeat, an unsuccessful rebellion followed in 1814, and in 1815 the Second Serbian Uprising began. In 1817, Serbia was "de facto" independent (as Principality of Serbia).