Siege of Vienna The Siege of Vienna in 1529 was the first attempt by the Ottoman Empire , led by Suleiman the Magnificent , to capture the city of Vienna , Austria . The siege signalled the pinnacle of the Ottoman Empire ' s power and the maximum extent of Ottoman expansion in central Europe . Thereafter , 150 years of bitter military tension and reciprocal attacks ensued , culminating in the Battle of Vienna of 1683 , which marked the start of the 15 - year long Great Turkish War . The inability of the Ottomans to capture Vienna in 1529 turned the tide against almost a century of conquest throughout eastern and central Europe . The Ottoman Empire had previously annexed Central Hungary and established a vassal state in Transylvania in the wake of the Battle of Mohács . According to Toynbee , " The failure of the first [ siege of Vienna ] brought to a standstill the tide of Ottoman conquest which had been flooding up the Danube Valley for a century past . " There is speculation by some historians that Suleiman ' s main objective in 1529 was actually to assert Ottoman control over the whole of Hungary , the western part of which ( known as Royal Hungary ) was under Habsburg control . The decision to attack Vienna after such a long interval in Suleiman ' s European campaign is viewed as an opportunistic manoeuvre after his decisive victory in Hungary . Other scholars theorise that the suppression of Hungary simply marked the prologue to a later , premeditated invasion of Europe . Background . " Main article in Battle of Mohács and Campaign of Ferdinand I " 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 ; Louis was killed . The Archduke of Austria , Ferdinand I of Habsburg , who was the brother of Holy Roman Emperor Charles V , claimed the vacant Hungarian throne in right of his wife , Anna of Bohemia and Hungary , sister to the childless ( and thus heirless ) Louis . Ferdinand won recognition only in western Hungary ; while 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 Royal Hungary and Ottoman Hungary up until 1700 . Following the Diet of Pozsony ( modern Bratislava ) on 26 October , Ferdinand was declared King of Royal Hungary due to his marriage to Louis ' sister and his own sister being the widow of Louis , who perished at Mohács . 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 . Ottoman army . In the spring of 1529 , Suleiman mustered a great army in Ottoman Bulgaria , with the aim of securing control over all of Hungary and reducing the threat posed at his new borders by Ferdinand I and the Holy Roman Empire . Estimates of Suleiman ' s army vary widely from 120 , 000 to more than 300 , 000 men mentioned by various chroniclers . There is some tendency by later , 18th - century European historians to exaggerate these figures to overstate the bravery of the outnumbered defenders of Vienna . 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 of Moldavia and the Serbs . 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 former Greek slave called Ibrahim Pasha , as " Serasker " , a commander with powers to give orders in the sultan ' s name . Suleiman launched his campaign on 10 May 1529 and faced numerous obstacles from the onset . 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 , unused 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 . 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 Spanish musketeers sent by Charles V . 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 . Siege . The Ottoman army which arrived in late September had been somewhat depleted during the long advance into Austrian territory , leaving Suleiman short of camels and heavy artillery . Many of his troops arrived at Vienna in a poor state of health after the tribulations of a long march through the thick of the European wet season and of those fit to fight , a third were light cavalry , or " 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 . Suleiman ' s 300 remaining light artillery pieces and cannons immediately commenced bombarding Vienna ' s walls , but the barrage failed to significantly damage the Austrian defensive earthworks . 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 sapper s , and in one case almost capturing Ibrahim Pasha . The defending forces detected and successfully detonated several mines intended to bring down the city ' s walls , subsequently dispatching 8 , 000 men on 6 October to attack the Ottoman mining operations , destroying many of the tunnels but sustaining serious losses when the confined spaces hindered their retreat into the city . More rain fell on 11 October , and with the Ottomans failing to make any breaches in the walls , the prospects for victory began to fade rapidly . In addition , Suleiman was facing critical shortages of supplies such as food and water , while casualties , sickness , and desertions began taking a toll on his army ' s ranks . The janissaries began voicing their displeasure at the progression of events , demanding a decision on whether to remain or abandon the siege . The Sultan convened an official council on 12 October to deliberate the matter . It was decided to attempt one final , major assault on Vienna : an " all or nothing " gamble . Extra rewards were offered to the troops . However , this assault was also beaten back as once again , the arquebus es and long pikes of the defenders prevailed . Unseasonably heavy snowfall made conditions go from bad to worse . The Ottoman retreat turned into a disaster with much of the baggage and artillery abandoned or lost in rough conditions , as were many prisoners . The receding army suffered an attack at Pozsony ( modern Bratislava ) , a short distance from Vienna , as Suleiman ' s force made its way east back to Ottoman Hungary . Aftermath . Some historians speculate that Suleiman ' s final assault was not necessarily intended to take the city but to cause as much damage as possible and weaken it for a later attack , a tactic he had employed at Buda in 1526 . Suleiman would lead another campaign against Vienna in 1532 , but it never truly materialised as his force was stalled by the Croatian Captain Nikola Jurišić during the Siege of Güns ( Kőszeg ) . Nikola Jurišić with only 700 – 800 Croatian soldiers managed to delay his force until winter closed in . Charles V , now largely aware of Vienna ' s vulnerability and weakened state , assembled 80 , 000 troops to confront the Ottoman force . Instead of going ahead with a second siege attempt the Ottoman force turned back , laying waste to the south - eastern Austrian state of Styria in their retreat . The two Viennese campaigns in essence marked the extreme limit of Ottoman logistical capability to field large armies deep in central and western Europe at the time . The army made its way back to Constantinople where it was stationed for the winter , so that its troops could attend to their fiefdoms and recruit for the next year ' s campaigning . The invasion and its climactic siege exacted a heavy toll upon both sides , with tens of thousands of soldiers and civilians left dead in its wake . However , it was a milestone which marked the end of Suleiman ' s expansion toward the centre of Europe and arguably the beginning of the stagnation and decline of the Ottoman Empire as the dominant power of the Renaissance world . The German historian Robert Adolf Kann remarked : " The delivery of Vienna by a brave garrison under Count Niklas Salm in 1529 , was probably a greater though less spectacular achievement than the liberation five generations later brought about primarily by the efforts of a rather large army of combined imperial and Polish forces " . Suleiman ' s retreat however did not mark a complete failure . The campaign underlined and maintained Ottoman control of the southern Pannonian Plain and left behind a trail of collateral damage in the neighbouring Habsburg Hungary and Austria that impaired Ferdinand ' s capacity to mount a sustained counter - attack . Suleiman ' s achievement was to consolidate the gains of 1526 and further establish the puppet kingdom of John Zápolya as a buffer state against the Holy Roman Empire . Ferdinand I erected a funeral monument for the German mercenary Niklas Graf Salm , head of the mercenary relief force dispatched to Vienna , as a token of appreciation to his efforts . Niklas survived the initial siege attempt but had been injured during the last Ottoman assault and died on 4 May 1530 . The Renaissance sarcophagus is now on display in the baptistery of the Votivkirche cathedral in Vienna . Ferdinand ' s son , Maximilian II , later built the Castle of Neugebaeude on the spot where Suleiman is said to have pitched his tent during the siege . Once the Ottoman empire ' s drive in Central Europe was checked , the Ottomans directed their efforts towards the Mediterranean . Having successfully forced out the Knights of Saint John from Rhodes in the Second Siege of Rhodes in 1522 , the stage was set for a climactic battle in 1565 between the Christian forces of the Knights Hospitaller and the Maltese in the Siege of Malta .