and the enlarged powers of a boyar circle in the Divan. In parallel, Wallachia became the battleground in a succession of wars between the Ottomans on one side and Russia or the Habsburg monarchy on the other. Mavrocordatos himself was deposed by a boyar rebellion, and arrested by Habsburg troops during the Austro-Turkish War of 1716–18, as the Ottomans had to concede Oltenia to Charles VI of Austria (the Treaty of Passarowitz). The region, organized as the Banat of Craiova and subject to an enlightened absolutist rule that soon disenchanted local boyars, was returned to Wallachia in 1739 (the Treaty of Belgrade, upon the close of the Austro-Russian–Turkish War (1735–39)). Prince Constantine Mavrocordatos, who oversaw the new change in borders, was also responsible for the effective abolition of serfdom in 1746 (which put a stop to the exodus of peasants into Transylvania); during this period, the ban of Oltenia moved his residence from Craiova to Bucharest, signalling, alongside Mavrocordatos' order to merge his personal treasury with that of the country, a move towards centralism. In 1768, during the Fifth Russo-Turkish War, Wallachia was placed under its first Russian occupation (helped along by the rebellion of Pârvu Cantacuzino). The Treaty of Küçük Kaynarca (1774) allowed Russia to intervene in favour of Eastern Orthodox Ottoman subjects, curtailing Ottoman pressures—including the decrease in sums owed as tribute—and, in time, relatively increasing internal stability while opening Wallachia to more Russian interventions. Habsburg troops, under Prince Josias of Coburg, again entered the country during the Russo-Turkish-Austrian War, deposing Nicholas Mavrogenes in 1789. A period of crisis followed the Ottoman recovery: Oltenia was devastated by the expeditions of Osman Pazvantoğlu, a powerful rebellious pasha whose raids even caused prince Constantine Hangerli to lose his life on suspicion of treason (1799), and Alexander Mourousis to renounce his throne (1801). In 1806, the Russo-Turkish War of 1806–12 was partly instigated by the Porte's deposition of Constantine Ypsilantis in Bucharest—in tune with the Napoleonic Wars, it was instigated by the French Empire, and also showed the impact of the Treaty of Küçük Kaynarca (with its permissive attitude towards Russian political influence in the Danubian Principalities); the war brought the invasion of Mikhail Andreyevich Miloradovich. After the Peace of Bucharest, the rule of Jean Georges Caradja, although remembered for a major plague epidemic, was notable for its cultural and industrial ventures. During the period, Wallachia increased its strategic importance for