Answer
The Treaty of Belgrade, signed in 1739 during the reign of Sultan Mahmud I, not Suleiman II, marked the end of the Austro-Turkish War of 1737–1739. It resulted in territorial gains for the Ottoman Empire, including the return of Belgrade and northern Serbia, as well as parts of Wallachia and Bosnia. The treaty solidified Ottoman control over the Balkans and secured its borders with the Habsburg monarchy for several decades.