The 1529 siege of Vienna was the first attempt by the Ottoman Empire to capture the city of Vienna in the Archduchy of Austria, part of the Holy Roman Empire. Suleiman the Magnificent, sultan of the Ottomans, attacked the city with over 100,000 men, while the defenders, led by Niklas Graf Salm, numbered no more than 21,000. Nevertheless, Vienna was able to survive the siege. The siege ultimately lasted just over two weeks, from 27 September to 15 October 1529.
The siege came in the aftermath of the 1526 Battle of Mohács, which had resulted in the death of Louis II, King of Hungary and the descent of the kingdom into civil war. Following Louis' death, rival factions within Hungary selected two successors: Archduke Ferdinand I of Austria, supported by the House of Habsburg, and John Zápolya. Zápolya would eventually seek aid from, and become a vassal of the Ottoman Empire, after Ferdinand began to take control of western Hungary, including the city of Buda.
The Ottoman attack on Vienna was part of the empire's intervention into the Hungarian conflict. In the short term, the Ottomans sought to secure Zápolya's position. Historians offer conflicting interpretations of the Ottomans' long-term goals, including the motivations behind the choice of Vienna as the campaign's immediate target. Some modern historians suggest that Suleiman's primary objective was to assert Ottoman control over all of Hungary, including the western part (known as Royal Hungary) that was then still under Habsburg control. Some scholars suggest Suleiman intended to use Hungary as a staging ground for further invasion of Europe.It was an "afterthought towards the end of a season of campaigning". Riley-Smith, p. 256; "A last-minute decision following a quick victory in Hungary". Shaw and Shaw, p. 94; Other historians, including Stephen Turnbull, regard the suppression of Hungary as the calculated prologue, to an invasion further into Europe: "John Szapolya became a footnote in the next great Turkish advance against Europe in the most ambitious campaign of the great Sultan's reign." Turnbull, p .50.
The failure of the siege of Vienna marked the beginning of 150 years of bitter military tension between the Habsburgs and Ottomans, punctuated by reciprocal attacks and culminating in a second siege of Vienna in 1683.
Background
In August 1526, Sultan Suleiman I decisively defeated the forces of King Louis II of Hungary at the Battle of Mohács, paving the way for the Ottomans to gain control of south-eastern Hungary; the childless King Louis died, possibly drowning when he attempted to escape the battlefield. His brother-in-law, Archduke Ferdinand I of Austria, brother of Holy Roman Emperor Charles V, claimed the vacant Hungarian throne. Ferdinand won recognition only in western Hungary; a noble called John Zápolya, from a power-base in Transylvania, challenged him for the crown and was recognised as king by Suleiman in return for accepting vassal status within the Ottoman Empire. Thus Hungary became divided into three zones: Royal Hungary, Ottoman Hungary and the Principality of Transylvania, an arrangement which persisted until 1700.
Following the Diet of Pozsony (modern Bratislava) on 26 October,Turnbull, Stephen. The Ottoman Empire 1326–1699. New York: Osprey, 2003. p. 49 Ferdinand was declared king of Royal Hungary due to the agreement between his and Louis's families, cemented by Ferdinand's marriage to Louis's sister Anna and Louis's marriage to Ferdinand's sister Mary. Ferdinand set out to enforce his claim on Hungary and captured Buda in 1527, only to relinquish his hold on it in 1529 when an Ottoman counter-attack stripped Ferdinand of all his territorial gains.Turnbull, Stephen. The Ottoman Empire 1326–1699. New York: Osprey, 2003. pp. 49–50
Prelude
Ottoman army
In the spring of 1529, Suleiman mustered a large army in Ottoman Bulgaria, with the aim of securing control over all of Hungary at his new borders by Ferdinand I and the Holy Roman Empire. While contemporary 16th-century chroniclers and older histories frequently cited exaggerated figures ranging from 120,000 to over 300,000 men, modern historical consensus estimates Suleiman's actual combat force at the walls of Vienna to have been between 75,000 and 100,000 men, with the remainder consisting of logistics, baggage trains, and rear garrisons.Turnbull suggests Suleiman had "perhaps 120,000" troops when he reached Osijek on 6 August. Turnbull, p. 50; Very high figures appear in nineteenth-century histories, for example that of Augusta Theodosia Drane in 1858, "more than 300,000 men"; such estimates may derive from contemporary accounts: the Venetian diarist Marino Sanuto, on 29 October 1529, for example, recorded the Turkish army as containing 305,200 men (mentioned in Albert Howe Lyber's The Government of the Ottoman Empire in the Time of Suleiman the Magnificent, p. 107). Modern books sometimes repeat the higher figures—for example, Daniel Chirot, in The Origins of Backwardness in Eastern Europe, 1980, p. 183, says "some 300,000 men besieged Vienna in 1529"; an alternative figure appears in Islam at War: "The sultan's army of 250,000 appeared before the gates of Vienna in the first siege of that great city", Walton, et al., 2003, p. 104. As well as numerous units of Sipahi, the elite mounted force of the Ottoman cavalry, and thousands of janissaries, the Ottoman army incorporated a contingent from Moldavia and renegade Serbian warriors from the army of John Zápolya.E. Liptai: Magyarország hadtörténete I. Zrínyi Military Publisher 1984. p. 165. Suleiman acted as the commander-in-chief (as well as personally leading his force), and in April he appointed his Grand Vizier (the highest Ottoman minister), a Greek former slave called Ibrahim Pasha, as Serasker, a commander with powers to give orders in the sultan's name.In April, the diploma by which Suleiman confirmed Ibrahim Pasha's appointment as serasker included the following: "Whatever he says and in whatever manner he decides to regard things, you are to accept them as if they were the propitious words and respect-commanding decrees issuing from my own pearl-dispensing tongue." Quoted by Rhoads Murphey in Ottoman Warfare 1500–1700, p. 136.
Suleiman launched his campaign on 10 May 1529 and faced numerous obstacles from the onset.Turnbull, pp. 50–51. The spring rains that are characteristic of south-eastern Europe and the Balkans were particularly heavy that year, causing flooding in Bulgaria and rendering parts of the route used by the army barely passable. Many large-calibre cannons and artillery pieces became hopelessly mired or bogged down, leaving Suleiman no choice but to abandon them, while camels brought from the empire's Eastern provinces, not used to the difficult conditions, were lost in large numbers. Sickness and poor health became common among the janissaries, claiming many lives along the perilous journey.
Suleiman arrived in Osijek on 6 August. On the 18th he reached the Mohács plain, to be greeted by a substantial cavalry force led by John Zápolya (which would later accompany Suleiman to Vienna), who paid him homage and helped him recapture several fortresses lost since the Battle of Mohács to the Austrians, including Buda, which fell on 8 September.Stavrianos, p. 77. The only resistance came at Pozsony, where the Turkish fleet was bombarded as it sailed up the Danube.
Defensive measures
As the Ottomans advanced towards Vienna, the city's population organised an ad-hoc resistance formed from local farmers, peasants, and civilians determined to repel the inevitable attack. The defenders were supported by a variety of European mercenaries, namely German Landsknecht pikemen and professional Spanish harquebusiers, sent by Charles V, who was Holy Roman Emperor and King of Spain.Ferdinand I had withdrawn to the safety of Habsburg Bohemia following pleas for assistance to his brother, Emperor Charles V, who was too stretched by his war with France to spare more than a few Spanish infantry to the cause.Reston, James Jr, Defenders of the Faith: Charles V, Suleyman the Magnificent, and the Battle for Europe, 1520–1536, Marshall Cavendish, 2009, p. 288,
Queen Mary of Hungary, who was the sister of Charles V, in addition to 1,000 German Landsknechts under Count Niklas Salm, sent a contingent of 700–800 Spanish harquebusiers. Only 250 Spanish survived.
The Spanish were under the command of Marshal Luis de Ávalos, with captains Juan de Salinas, Jaime García de Guzmán, Jorge Manrique, and Cristóbal de Aranda. This elite infantry excelled in the defense of the northern area and with discretion fire prevented the Ottomans from settling in the Danube meadows, near the ramparts, where they could have breached with enough space to work. These elite soldiers also built additional palisades and trap pits that would be essential during the siege.
The Hofmeister of Austria, Wilhelm von Roggendorf, assumed charge of the defensive garrison, with operational command entrusted to a seventy-year-old German mercenary named Nicholas, Count of Salm, who had distinguished himself at the Battle of Pavia in 1525. Salm arrived in Vienna as head of the mercenary relief force and set about fortifying the three-hundred-year-old walls surrounding St. Stephen's Cathedral, near which he established his headquarters. To ensure the city could withstand a lengthy siege, he blocked the four city gates and reinforced the walls, which in some places were no more than six feet thick, and erected earthen bastions and an inner earthen rampart, levelling buildings where necessary to clear room for defences.
Pavle Bakić, the last titular of the Serbian Despotate and ally of Ferdinand, provided 2,000 Serbian hussar cavalry to the defence of Vienna.
Siege
The Ottoman army that arrived in late September had been depleted during the long advance into Austrian territory, leaving Suleiman short of camels and heavy artillery. Many of his troops arrived at Vienna in poor health after the tribulations of the long march through the worst of the wet season. Of those fit to fight, a third were Sipahis, ill-suited for siege warfare. Three richly dressed Austrian prisoners were dispatched as emissaries by the Sultan to negotiate the city's surrender; Salm sent three richly dressed Muslims back without a response.
As the Ottoman army settled into position, the Austrian garrison launched sorties to disrupt the digging and mining of tunnels below the city's walls by Ottoman sappers, in one case almost capturing Ibrahim Pasha. The first units to attack the Ottomans were mounted Serbian hussars under the command of Pavle Bakić. The defending forces detected and successfully detonated several mines that had been intended to breach the walls. On 6 October, 8,000 men were dispatched to attack the Ottoman mining operations. They succeeded in destroying many of the tunnels, but they sustained heavy losses when the confined space hindered their return to the city.