The Treaty of Belgrade, also known as the Belgrade Peace, was a peace treaty between the Habsburg Monarchy and Ottoman Empire, that was signed on September 18, 1739, in Belgrade (modern Serbia), thus ending the Austro-Turkish War (1737–1739). Agreed territorial changes were substantial, and also favorable for the Ottoman side, since Habsburgs had to cede three regions: the Banat of Craiova (modern Oltenia), the Kingdom of Serbia with Belgrade, and Bosnian section of Posavina, thus placing the newly defined Habsburg-Ottoman border on the rivers Sava and Danube.
Negotiations
During the final stages of the Austro-Turkish War (1737–1739), the main Habsburg army, commanded by field marshal Wallis suffered a strategic defeat at the Battle of Grocka (21–22 July 1739), and retreated into the Belgrade Fortress, that was soon besieged by the Ottoman forces.
Already on 31 July, the government in Vienna decided to relieve Wallis of his previously granted powers to negotiate with the Ottomans. Those powers were transferred to count Neipperg. On 10 August, the imperial government composed new instructions, that were approved by the emperor Charles VI and sent to Neipperg on 11 August. Arriving in the still Habsburg-held Belgrade with imperial instructions on 16 August, Neipperg proceeded to the camp of the Grand Vizier on 18 August. There he found himself increasingly isolated, and dependent on the French mediator, marquis Louis Sauveur de Villeneuve. On 1 September, Neipperg agreed to sign a preliminary peace agreement with the Ottomans, and then dispatched the news to the Emperor on the next day. Neipperg's report arrived to Vienna on 7 September, provoking outrage, since it became obvious that he signed the agreement not knowing that already on 31 August, the Emperor sent him new instructions, an action that was followed by the governments decision to revoke Neipperg's negotiating powers (3 September). On 5 September, while still not knowing that the preliminary treaty was already signed, the Emperor sent a letter to Neipperg, informing him that his diplomatic mission has ended. Only upon return to Belgrade from the Grand Vizier's camp, Neipperg became aware of those new instructions and consequent decisions, realizing that he acted without valid negotiating powers, but it was too late for reversal, and further negotiations proceeded towards the conclusion of the final peace treaty.
Treaty
After some further negotiations, the final peace treaty was concluded on 18 September. It was also signed in the Grand vizier's camp near Belgrade. By the Treaty of Belgrade, the Habsburgs agreed to cede three provinces to the Ottomans: the Banat of Craiova (modern Oltenia), the Kingdom of Serbia with Belgrade, and Bosnian section of Posavina. All of those territories were previously gained for the Habsburg Monarchy by the Treaty of Passarowitz in 1718, and remained under Habsburg rule until 1739. New demarcation line, under the Treaty of Belgrade, was set at the rivers Sava and Danube.
The Treaty of Belgrade effectively ended the existence of the Habsburg-held Kingdom of Serbia, which had existed since 1718. The retreat of Habsburg forces was followed by a major Serbian migration from the territories ceded to the Ottoman Empire. These Serbian lands remained under Ottoman rule until the next Habsburg-Ottoman war (1788–1791), during which they were again temporarily occupied by Habsburg forces in 1788–1789, with the support of Serbian rebels.
The treaty is also notable for being one of the last international treaties to be written in Latin.
Aftermath
The Habsburg decision to enter negotiations in August 1739 forced its ally Russia to also accept peace talks, through French mediation, that resulted in a separate preliminary peace treaty that was signed on the same day (18 September) in Belgrade, and was later finalized by the Treaty of Niš (3 October), thus ending the Russo-Turkish War (1735–1739).
After the formal ratification of both peace treaties, diplomatic instruments were exchanged and the final convention was signed in Constantinople on 28 December 1739, also through the French mediation, thus concluding the war. In the meantime, both count Neipperg and field marshal Wallis were arrested by the Habsburg state authorities and accused for the unfavorable outcome of negotiations. Only after the Emperor's death in 1740 they were pardoned.