Battle of Vienna - Events During The Siege

Events During The Siege

The main Ottoman army finally laid siege to Vienna on 14 July. On the same day, Kara Mustafa sent the traditional demand for surrender to the city.

Ernst Rüdiger Graf von Starhemberg, leader of the remaining 15,000 troops and 8,700 volunteers with 370 cannons, refused to capitulate. Only days before, he had received news of the mass slaughter at Perchtoldsdorf, a town south of Vienna whose citizens had handed over the keys of the city after having been given a similar choice.

The Viennese had demolished many of the houses around the city walls and cleared the debris, leaving an empty plain that would expose the Ottomans to defensive fire if they tried to rush the city. Kara Mustafa Pasha solved that problem by ordering his forces to dig long lines of trenches directly toward the city, to help protect them from the defenders as they advanced steadily toward the city.

The Ottomans had 130 field guns and 19 medium-caliber cannons which were insufficient against the defenders 370 cannons. The fortifications of Vienna were very strong and up to date, and the Ottomans had to find a more effective use for their gunpowder: mining. Tunnels were dug under the massive city walls to blow them up with substantial quantities of black powder.

The lack of urgency by the Ottomans at this point, combined with the delay in advancing their army after declaring war, eventually allowed a relief force to arrive. Historians have speculated that Kara Mustafa wanted to take the city intact for its riches, and declined an all-out attack in order to prevent the right of plunder which would accompany an assault.

The Ottoman siege cut virtually every means of food supply into Vienna, and the garrison and civilian volunteers suffered extreme hardships. Fatigue became such a problem that Graf Ernst Rüdiger von Starhemberg ordered any soldier found asleep on watch to be shot. Increasingly desperate, the forces holding Vienna were on their last legs when in August, Imperial forces under Charles V, Duke of Lorraine beat Imre Thököly of Hungary at Bisamberg, 5 km northwest of Vienna.

On 6 September, the Poles under Jan III Sobieski crossed the Danube 30 km north west of Vienna at Tulln, to unite with the Imperial troops and the additional forces from Saxony, Bavaria, Baden, Franconia and Swabia. France declined to help its Habsburg rival. Louis XIV of France chose to use the opportunity to invade the western territories of the Holy Roman Empire, mainly Alsace .

During early September, the experienced 5,000 Ottoman sappers repeatedly blew up large portions of the walls, the Burg bastion, the Löbel bastion and the Burg ravelin in between, creating gaps of about 12m in width. The Viennese tried to counter by digging their own tunnels, to intercept the depositing of large amounts of gunpowder in subterranean caverns. The Ottomans finally managed to occupy the Burg ravelin and the Nieder wall in that area on 8 September. Anticipating a breach in the city walls, the remaining Viennese prepared to fight within the city walls.