On 12 September 1683, the Ottomans were routed by the forces of Europe at the Battle of Vienna. In early 1684, Austria, Poland and Venice concluded an anti-Ottoman pact; they were joined by Russia in 1686 to form the Holy League. It was clear at that time that the decisive moment was near. The leaders of Chiprovtsi assessed that after the imminent capture of Belgrade by the League in 1688 their European allies would reach Sofia and end the Ottoman rule of Bulgaria. Thus, they revolted in the spring of 1688. The reach of the uprising cannot be exactly determined, but scholars such as S. Damyanov believe it included Chiprovtsi and the neighbourhing Kopilovtsi, Klisura and Zhelezna and thousands of Bulgarians from the entire Bulgarian northwest. Although the leaders were mostly Catholics, the bulk of the insurgents were Orthodox. It is known that the rebellion was led by over 200 "voivodes" of separate detachments. The insurgents were aided by six regiments of regular Habsburg army and artillery under General Heißler and managed to briefly capture the town of Kutlovitsa (modern Montana), but were ultimately crushed by the Ottomans and their Hungarian ally Imre Thököly. On 18–19 October, the Ottomans stormed Chiprovtsi and retook it from the rebels, capturing over 2,000 people. About 3,000 natives of the area, guarded by the remaining insurrectionary units, managed to flee beyond the Danube. Most of those settled in the Habsburg-ruled realms, founding a major Bulgarian colony in the Banat known as the "Banat Bulgarians", as well as colonies in Deva and Alvinc (Vinţu de Jos) in Transylvania and Szentendre in modern Hungary. The town itself was plundered, burned down and deserted and its links to the West were largely severed.