Complex sentence: Under Köprülü's leadership the Ottomans halted an Austrian advance into Serbia and crushed an uprising in Bulgaria until Köprülü Fazıl Mustafa Pasha was killed in the Battle of Slankamen by Austrian forces.
Split into simpler sentences: Under Köprülü's leadership the Ottomans halted an Austrian advance into Serbia and crushed an uprising in Bulgaria. Until Köprülü Fazıl Mustafa Pasha was killed in the Battle of Slankamen by Austrian forces.