On September 27, 1529, Suleiman the Magnificent laid siege to Vienna. For this purpose, he gathered an army of 120,000 men, unprecedented for his time, with 300 cannons and 20,000 camels. In addition to Spahis and Janissaries, Suleiman the Magnificent's army also included Moldavians and Serbs.
The garrison of Vienna numbered nearly 17,000 soldiers and 75 cannons.
Able Austrian general Wilhelm von Rogendorf takes command of the garrison, and operational leadership is entrusted to 70-year-old German mercenary Niklas Graf Salm.
Austrian Archduke Ferdinand I Habsburg presciently left Vienna and it was defended by only 20,000 men, supported by strong fortress walls. Until October 14, Suleiman I made several unsuccessful attacks on Vienna. The defenders of the Austrian capital show extraordinary heroism.
Ottoman soldiers are experiencing an acute shortage of foodstuffs and grumble loudly against the cold, unaccustomed to Asians. The Sultan and the army fear that they will not be able to return to their homes until the cold of winter sets in. Additionally, epidemics break out in the camp of the Ottoman army.
All this forced Suleiman I to lift the siege of Vienna and head back to Istanbul, where he arrived in December 1529. Suleiman I the Magnificent suffered his first major defeat.
Ferdinand I erected a tombstone in honor of the defender of Vienna - Niklas Graf Salm, who was wounded in the last Ottoman attack and died on May 4, 1530. His sarcophagus is now exhibited in the baptistery of the Fautifkirche church in Vienna.