In 1529, the Ottomans had moved up the Danube and besieged Vienna. The army which Suleiman
the Magnificent sent against Vienna in 1529 consisted of 325,000 men, 500 artillery pieces and
90,000 camels. Providing for the camel’s daily diet of barley and straw was often forced upon locals
by corrupt Ottoman dignitaries, locals who then levied taxes to pay for camels hired by the state.
There were different jobs for camels and the wagons drawn by horses or oxen, the camels usually
being used for longer trips and even preferred for use over sea routes at times. While drenching rains
made it impossible for most of the Ottoman camels to maneuver, and many of their soldiers lay ill,
the sight of tents as far as they could see still terrified besieged Vienna.

Operational command of the defence was given to a 70 year-old German mercenary named Nicholas
Graf von Salm, a noble of the Principality of Salm-Salm (at the time a German state of the Holy
Roman Empire), who had been hastily appointed in response to Suleiman’s looming threat. Salm had
arrived with 1,000 German Landsknechte, a formidable group of mercenary pikemen, and another
700 Spanish musketmen. He would be taking charge of the garrison of 23,000 infantry, 2,000
cavalry and 75 cannon.

Many of the walled city’s leaders had fled in apprehension, and although Salm had previously
ordered 4,000 women, children, and elderly out of the city with escorts, most of the group was
slaughtered at Traismauer, with many impaled on stakes and some young women taken to be sold as
slaves. Now, the defense of Europe lay in his hands, and he faced a fierce and despised adversary
against great odds. Had Salm failed, the entire history of Europe would have been radically different.  

Suleiman commenced a cannonade against the city walls, but this was simply a diversion for his
clever plan to undermine Viennese defenses by quietly constructing a network of tunnels under the
Viennese gates in which explosives were to be placed. Having discovered Suleiman’s plan, Salm's
spies allowed him to discern the approximate locations of the passages, and he authorized excavation
of counter-tunnels to intercept the Ottomans and collect the mines before they could be detonated.  

The would result in the world’s first and possibly only recorded instance of a pitched underground
battle.  Once the Austrians located and infiltrated the Ottoman tunnels, the two sides soon confronted
each other in the near darkness beneath the earth.  To avoid explosions, the combatants had to
refrain from discharging their firearms and instead, waged brutal hand-to-hand combat

Although most mines were located and defused, the Ottomans eventually breached and toppled a
crucial Viennese gate and its defensive tower, and they charged the city center with cavalry and a
Janissary vanguard. Salm and his well-trained defensive garrison cut down the attackers with deadly
pikes and forced them back. Salm brilliantly defended the city and frightened the Ottomans with his
cunning and he then decimated the Ottoman forward ranks with an explosive attack on their tents.

Through various clever maneuvers, the Turks were led to believe they were outnumbered and,
sensing hopelessness, they surprisingly and quickly packed their campsites, throwing their captured
Austrian prisoners into a large fire. Many Austrian captives managed to escape to the walls of the
city, where ladders were lowered for them; for the Viennese were still not sure if it was all over and
safe enough to come out. Each man let into Vienna after the siege was examined for circumcision,
believing the Turks had smuggled in spies. Those that failed the test were hanged.

The next day it snowed, and Vienna's defenders carefully emerged from their fortress. Ottoman
casualties were thought to have been around 20,000 to 25,000, many more than those of the city's,
although most of Austria south of Vienna was brutally de-populated. Although the Ottomans
continued to instil fear well into the sixteenth century, internal struggles began to deteriorate the once
overwhelming military supremacy of the Ottoman Empire. European confidence increased as they
began to score victories against the Turks, yet the Ottoman Empire invaded Moldavia in 1538 and
took Buda and Pest in 1541.

The surviving Ottoman army of 35-40,000 men was not enough for Suleiman to take on Vienna
again soon, and in 1547 a temporary truce was signed between the Habsburg and Ottoman Empires.

Note: Graf Nicholas zu Salm-Reifferscheidt's Principality of Salm-Salm was at the time a German
state of the Holy Roman Empire. In 1790, after the French Revolution, the princes of Salm were
forced to flee the territory and they moved to their castle in Anholt, Westphalia. Salm-Salm then
was besieged by the revolutionary army, which blocked food supplies from reaching the state, and
as a consequence, the population was forced to surrender to France on March 2, 1793.
The First Siege of Vienna in 1529 and Nicholas Graf von Salm