Few battles have had such historic significance as the Siege of Vienna in 1529. While compiling a list of significant historic battles, sieges, and wars, it is likely that events such as those at Macedon, the Teutoburg Forest, Bannockburn, Poitiers, and Agincourt will all be mentioned, but the Siege of Vienna in 1529 is often sadly overlooked.In this article, we will explore how and why this siege was so significant, and why it marked the pinnacle of European warfare against the Ottoman Empire.Origins of the Siege of ViennaBattle of Vienna, 1683. Source: Wikimedia CommonsThe Siege of Vienna in 1529 was not a standalone battle or siege. Rather, it was a part of the Habsburg-Ottoman Wars in Hungary, which had started in 1526. These wars would eventually rage on in one form or another until 1568.In the early 16th century, the Habsburgs and the Ottoman Empire vied for control of border lands in southeast Europe, the Ottomans moving west from their base in modern-day Turkey, and the Habsburgs trying to control their territory in Central Europe.These military campaigns ultimately offered very few results in terms of territorial gains. The most important aspect of these wars from the European perspective was that everywhere west of Vienna remained culturally European (a part of Christendom in the 16th century) and still does to this day.For the Ottomans, the Siege of Vienna was a lost opportunity to further expand across the European continent, bringing Ottoman culture and the Islamic religion with them.The Ottoman PlanSuleiman the Magnificent, by Titian, c. 1530. Source: Wikimedia CommonsThe Ottoman Sultan, Suleiman the Magnificent, began planning for the Siege of Vienna in the spring of 1529. He gathered a large force in Ottoman Bulgaria, with the aim of taking control of all of Hungary at the new borders set by Ferdinand I, the Holy Roman Emperor.The size of Suleimans force has been debated by chroniclers and historians, with estimates ranging from 120,000 to well upwards of 300,000. Either way, Suleiman mustered a huge fighting force of well over 100,000 men.In his army, he also incorporated forces from Moldavia and Serbia to bolster his numbers, and the plan was formally launched on May 10, 1529.The March to ViennaStatue of Nicholas Salm. Source: Wikimedia CommonsHowever, things were not as smooth as Suleiman or any of his advisers had expected.The spring rains, which are a key characteristic of southeast Europe, and especially the Balkans, were extremely heavy that year, leading not only to delays in their progress, but huge logistical issues, too.For a start, the march from Bulgaria to Austria is hundreds of miles, and difficult enough even in pleasant conditions. Throw flooding into the mix, and it was a recipe for disaster.Water-borne diseases ran rampant throughout the caravan, and hundreds of men perished while still in the Balkans. In addition, the camels that Suleiman the Magnificent used for transport were unused to the terrain, and when the floods came, many camels also died.Another way to speed up the army involved ditching their heavy equipment. This meant that the majority of the Ottoman heavy artillery, such as cannons and siege weaponry, was abandoned.It was not until late September that the sultans forces reached the city walls of Vienna, months after they had initially planned the siege.The Preparations From the Viennese SideGerman mercenaries, by Daniel Hopfer and Erhard Schon, c. 15001530. Source: The Met, New YorkOnce word of the impending Ottoman attack reached the city, the whole community rallied. Defensive measures from peasants and farmers took place outside the city, while other European mercenaries traveled to Vienna to defend the city, including German pikemen and Spanish cavalrymen, sent by Charles V, the Holy Roman Emperor.The arrival of the Spanish seriously boosted morale, as these soldiers were known for their elite training and large successes on the battlefield. They built many pike walls around the city as a defensive measure, as well as pit traps for the advancing Ottoman army to fall into.A 70-year-old veteran named Nicholas, Count of Salm, was placed in charge of defensive operations of the city, and his name would go down in history as one of the finest military leaders ever.Salms first action was to protect the 300-year-old walls around St Stephens Cathedral (found in the center of the old town in Vienna today), where he made his headquarters.Because he knew a siege was coming, he made provisions for the city to withstand a lengthy siege and fortified the walls surrounding the city. Some were only just over six feet (1.8 meters) thick in places. He also blocked off the citys four main gates.Another significant contribution came from the last Serbian Despot, Pavle Baki, who provided 2,000 hussars to aid in Viennas defense.The SiegePanoramic view of the Siege of Vienna, by Nicholas Meldeman, c. 1530. Source: Wikimedia CommonsIt is important to remember that the Viennese only had around 17,000 to 21,000 men ready to defend not just the city, but Europe, against the mighty 100,000+ force of the Ottoman Empire.On paper, it was an easy Ottoman victory, and couldve been achieved in a day. However, the Ottoman success at the Fall of Constantinople in the previous century was not to be repeated.By the time the Ottoman forces arrived at the gates of Vienna, their numbers had been seriously depleted due to diseases spreading through the camp and numerous other causes, but they nevertheless still had a huge numerical advantage over the defenders.Around September 27, when the Ottomans settled into position, the Austrian defenders launched attacks against the Ottomans, who had begun to dig tunnels under the city walls to breach them. In one of these attacks, or sorties, Ibrahim Pasha (Suleiman the Magnificents first in command) was almost captured.The mounted Serbian hussars, which Pavle Baki had supplied, were the first troops to formally attack the Ottomans. It was these forces that detected several mines which had been intended to breach the walls, giving another minor victory to the Austrians.The Relief of Vienna, by Frans Geffels, 1683-94. Source: Wikimedia CommonsOn October 6, around 8,000 Austrians were dispatched to deal with the Ottomans in hand-to-hand combat, and while they succeeded initially, many perished on their way back into the city due to the cramped entryways, where they were picked off by the Ottoman forces.As if the conditions that Suleiman had already endured werent bad enough already, the heaviest rainfall was still yet to come. On October 11, the heavens opened, drenching the already cold, wet, and severely depleted Ottoman forces, soaking their equipment and drowning their morale as well.Sickness, casualties, and even desertions had begun to take their toll on the Ottoman forces, and the prospect of a victory was rapidly slipping away. The following day, on October 12, Suleiman convened an official war council to discuss the strategy of the attack. It was decided that they would have one final, all-or-nothing, full-blown attack, and it was to take place on October 14.This was a huge gamble, and Suleiman knew it. Despite extra rewards promised for his troops and many thousands still behind him, the attack was a complete failure.The defenders use of long pikes and arquebuses (a very early form of gun) was enough to repel the Ottomans, condemning them to defeat. The following day, on October 15, with winter approaching and supplies running low, Suleiman the Magnificent formally called a withdrawal to Constantinople, leaving the Austrians as victors at the Siege of Vienna in 1529.The Aftermath of the Siege of ViennaThe Turkish Siege of Vienna, by August Querfurt, 1750s. Source: Wikimedia CommonsThe Ottoman forces were pursued for three days by Austrian troops, who rescued any prisoners that the Ottomans had managed to capture, as well as capturing Ottoman prisoners to bring back to Vienna.Heavy snowfall, unusual for that time of year, severely impacted the Ottoman retreat, and they did not reach Constantinople until December 16. This was a huge morale blow for the Ottomans, but it is merely a footnote in the life and legacy of Suleiman the Magnificent. The fact that he endured one of the most humiliating defeats in European military history and still holds the sobriquet the Magnificent shows how successful he was as a leader throughout his career.The Legacy of the Siege of ViennaViennas main cathedral, photo by Oksana Pylypenko. Source: UnsplashThe Siege of Vienna in 1529 was one of the most important victories in Early Modern European history, and in fact, in European history in general.It was not just a victory of morale as far as Christendom and Christianity were concerned (many minds harked back to the First and Third Crusades, given that Christendom had defeated Islam), it was a huge strategic victory, too.It meant that Europe knew that the Ottomans would not, and could not, venture any further west than Vienna, making Vienna one of the most important cities on the continent. It also meant that the Habsburgs, who had previously ignored pleas to modernize Viennas defenses, had to up their game. They were then forced to help fortify the city, should the Ottomans attack once again.These modernized fortifications would prove essential as Vienna withstood a second Ottoman attack in 1683, so if it had not been for the victory in 1529, it is very likely that Vienna would have fallen, due to either being taken over or the Habsburgs not fortifying the city properly.King John III Sobieski blessing the Polish attack on the Turks in Vienna, 1683, 1871. Source: Wikimedia CommonsThis period in the early to mid-16th century in Europe was also a turbulent time as far as religion was concerned. Henry VIII in England was on the verge of breaking with Rome, while the Protestant Reformation was gathering momentum on the continent at the same time.Therefore, an indirect consequence of the Siege of Vienna was that it helped the Protestant Reformation, because the Habsburgs and the Holy Roman Empire, who had been so fixated on internal religious conflicts, were thereby forced to withdraw their troops from these conflicts and instead focus on reinforcing Vienna. Protestant forces throughout the continent took advantage.Overall, the success of the Siege of Vienna was down to sheer military tactical genius from the defenders, aided by the natural weather conditions. It could even be argued that this victory was the reason that Europe has remained a largely Christian continent for so long, and why Islam has rarely taken a strong foothold to this day.