This is a reprint of an article I posted in 2006.
Over 300 years ago, Western Civilization was nearly overrun by Islam. The seeming unstoppable tide of Islam paused at Vienna. On September 11th, 1683, the king of Poland, John Sobieski, at the head of his Winged Hussars, the last heavy calvary in Europe, led an army down upon the besiegers. They swept the Muslim army from the field, and from that day, the grip of Islam upon Eastern Europe weakened.
This battle was the beginning of the end of the Ottoman Empire. If you click on the title of this post, you'll be directed to the orgininal article on answers.com, together with more links, pictures, and so on. ----------
Battle of Vienna Part of the Habsburg-Ottoman Wars of 1683-1697 The Battle of Vienna (Turkish: İkinci Viyana Kuşatması) (as distinct from the Siege of Vienna in 1529) took place on September 11 and September 12 1683 after Vienna had been besieged by Turks for two months.
It was the first large-scale battle of the Habsburg-Ottoman Wars, yet with the most far-reaching consequences. The siege itself began on 14 July 1683, by the Ottoman army commanded by Grand Vizier Merzifonlu Kara Mustafa Pasha. The decisive battle took place on 12 September, after the united relief army of 70,000 men had arrived, pitted against the Ottoman army of approximately 138,000 men - although a large number of these played no part in the battle, as only 50,000 were experienced soldiers, and the rest less motivated supporting troops .
King Jan III Sobieski of the Polish-Lithuanian Commonwealth had been made Commander in Chief of his own 30,000-man Polish forces and the 40,000 troops of Habsburg and their allies, led by Charles V, Duke of Lorraine. The battle marked the turning point in the 300-year struggle between the forces of the Central European kingdoms, and the Ottoman Empire. Over the sixteen years following the battle, the Habsburgs of Austria, and their allies gradually occupied and dominated southern Hungary and Transylvania, which had been largely cleared by the Turkish forces.
To capture the city of Vienna had long been a strategic aspiration for the Ottoman Empire, due to its inter-locking control over Danubean (Black Sea-to-Western Europe) southern Europe, and the overland (Eastern Mediterannean-to-Germany) trade routes. During the years preceding the second siege, under the auspicies of grand viziers from the influential Köprülü family, the Ottoman Empire undertook extensive logistical preparations this time, including the repair and establishment of roads and bridges leading into Austria, and logistical centers, as well as the forwarding of ammunition, cannons and other resources, from all over the Empire to these logistical centers, and into the Balkans.
Emperor Leopold I On the political front, the Ottoman Empire had been providing military assistance to the Hungarians and to non-Catholic minorities, in Habsburg-occupied portions of Hungary. There, in years preceding the siege, widespread unrest had become open rebellion, upon Leopold I's insistent pursuit of Counter-Reformation principles, and his burning desire of crushing Protestantism.
In 1681, Protestants and other anti-Habsburg forces, led by Imre Thököly, were reinforced with a significant force from the Ottomans, who recognized Imre as King of "Upper Hungary" (eastern Slovakia and parts of northeastern present-day Hungary, which he had earlier taken by force of arms, from the Habsburgs). This support went so far as explicitly promising the "Kingdom of Vienna" to the Hungarians, if it fell into Ottoman hands. Sultan Mehmed IV
Yet, before the siege, a state of peace had existed for twenty years between the Habsburgs and the Ottoman Empire, as a result of the Peace of Vasvár. In 1681 and 1682, clashes between the forces of Imre Thököly and the Habsburgs' military frontier (which was then northern Hungary) forces intensified, and the incursions of Habsburg forces into Central Hungary provided the crucial argument of Grand Vizier Kara Mustafa Pasha in convincing the sultan, Mehmet IV and his Divan, to allow the operation of the Ottoman Army. Mehmet IV authorized Kara Mustafa Pasha to operate as far as Győr (Turkish: Yanıkkale, German: Raab) and Komarom (Turkish: Komaron, German: Komorn) castles, both in northwestern Hungary, and to besiege them. The Ottoman Army was mobilized on January 21 1682, and war was declared on August 6 1682. "Jan III Sobieski at Vienna" However, the forward march of Ottoman Army elements did not begin until April 1 1683 from Edirne in Thracia.
This strategic mistake provided ample time (almost 15 months) for Habsburg forces to prepare their defense, and to set up alliances with other Central European rulers. During the winter, the Habsburgs and Poland concluded a treaty in which Leopold would support Sobieski if the Turks attacked Kraków; in return, the Polish Army would come to the relief of Vienna, if attacked. In the spring, the Turkish Army reached Belgrade in early May, then moved toward the city of Vienna. About 40,000 Tatar Forces arrived 40km east of Vienna on 7 July, twice as many as the Austrian forces in that area. After initial fights, Leopold retreats to Linz with 80,000 inhabitants of Vienna.
The King of Poland prepared a relief expedition to Vienna during the summer of 1683, honoring his obligations to the treaty. He went so far as to leave his own nation virtually un-defended when departing from Cracow on 15 August. Sobieski covered this with a stern warning to Imre Thököly, the leader of Hungary (then an Ottoman satellite), whom he threatened with destruction if he tried to take advantage of the situation - which Thököly did.
The main Turkish army finally invested Vienna on July 14. Graf Ernst Rüdiger von Starhemberg, leader of the remaining 11,000 troops and 5,000 citizens and volunteers, refused to capitulate. The Viennese had demolished many of the houses around the city walls and cleared the debris, leaving an empty plain that would expose the Turks to defensive fire if they tried to rush the city.
Kara Mustafa Pasha solved that problem by ordering his forces to dig long lines of trenches directly toward the city, to help protect them from the defenders as they advanced steadily toward the city. As their 300 cannons were outdated and the fortifications of Vienna were up to date, the Turks had a more effective use for the gun powder: undermining. Tunnels were dug under the massive city walls to blow them up with explosives, using Sapping mines.
The Ottomans had essentially two options to take the city: the first, an all-out assault, was virtually guaranteed success since they outnumbered the defendants almost 20-1. The second was to lay siege to the city, and against all military logic, they chose the second. Historians have speculated that Kara Mustafa wanted to take the city intact for its riches, and declined an all-out attack in order to prevent the right of plunder which would accompany such an assault. 
Additionally, the Ottoman siege cut virtually every means of food-supply into Vienna,  and the garrison and civilian volunteers suffered extreme casualties and fatigue became such a problem that Graf Ernst Rüdiger von Starhemberg ordered any soldier found asleep on watch to be shot.
Increasingly desperate, the forces holding Vienna were on their last legs when in August, Imperial forces under Charles V, Duke of Lorraine beat Imre Thököly of Hungary at Bisamberg, 5km north east of Vienna.
On 6 September, the Poles crossed the Danube 30km north west of Vienna at Tulln, to unite with the Imperial forces, and additional troops from Saxony, Bavaria, Baden, Franconia and Swabia which had answered the call for a Holy League that was supported by Pope Innocent XI.
Only Louis XIV of France, Habsburg's rival, not only declined to help, but used the opportunity to attack cities in Alsace and other parts of southern Germany, as in the Thirty Years' War decades earlier.
During early September, the experienced 5000 Turkish sappers repeatedly blew up large portions of the walls, the Burg bastion, the Löbel bastion and the Burg ravelin in between, creating gaps of about 12m in width. The Austrians tried to counter by digging their own tunnels, to intercept the deposition of large amounts of gun powder in subterranean caverns.
The Turks finally managed to occupy the Burg ravelin and the Nieder wall in that area on 8 September. Anticipating a breach in the city walls, the remaining Austrians prepared to fight in Vienna itself.
Staging the battle
The relief army had to act quickly, to save the city from the Turks, and to prevent another long siege in case they would take it. Despite the international composition and the short time of only six days, an effective leadership structure was established, undisputedly centered on the King of Poland and his heavy cavalry.
The motivation was high, as this war was not as usual for the interests of kings, but for Christian faith and even God. And, unlike the crusades, the battleground was in the heart of Europe. Kara Mustafa Pasha, on the other hand, was less effective despite having months of time to organize his forces, ensure their motivation and loyalty, and to prepare for the expected relief army attack.
He had entrusted defence of the rear to the Khan of Crimea and his cavalry force, which numbered about 30,000. There is serious questions as to how much the Tatar forces participated in the final battle at Vienna. Their Khan felt humiliated by repeated snubs by Kara Mustafa, and reportedly refused to make a strike against the Polish relief force as it crossed the mountains, where the heavy cavalry would have been vulnerable to such an assault from the lighthorse Tatars. 
Nor were they the only component of the Ottoman army to openly defy Mustafa, and to refuse assignments. This left vital bridges undefended and allowed passage of the combined Habsburg-Polish army, which arrived to relieve the siege.
Critics of this account say that it was Kara Mustafa Pasha, and not the Crimean Khan, who was held responsible for the failure of the siege.
The Holy League forces arrived on the "Kahlen Berg" (bare hill) above Vienna, signalling their arrival with bonfires. In the early morning hours of 12 September, before the battle, a mass is held for King Sobieski.
The battle started before all units were staged. Early in the morning at 4:00 , Turkish forces opened hostilities to interfere with the Holy League's troop deployment. A move forward was made by Charles, the Austrian army on the left, and the German forces in the center. Mustafa Pasha launched a counter-attack, with most of his force, but holding back parts of the elite Janissary and Sipahi for the invasion of the city.
The Turkish commanders had intended to take Vienna before Sobieski arrived, but time ran out. Their sappers had prepared another large and final detonation under the Löbelbastei, to provide access to the city. While the Turks hastily finished their work and sealed the tunnel to make the explosion more effective, the Austrian "moles" detected the cavern in the afternoon. One of them entered and defused the load just in time.
At that time, above the "subterranean battlefield", a large battle was going on, as also the Polish infantry had launched a massive assault upon the right flank. Instead of focusing on the battle with the relief army, the Turks tried to force their way into the city, carrying their crescent flag.
After 12 hours of fighting, Sobieski's Polish force held the high ground on the right. At about five o'clock in the afternoon, after watching the ongoing infantry battle from the hills for the whole day, four cavalry groups totalling 20,000 men, one of them Austrian-German, and the other three Polish, charged down the hills. The attack was led by the Polish king in front of a spearhead of 2000 heavily armed winged Polish lancer hussars.
This charge broke the lines of the Ottomans which were tired from the long fight on two sides. In the confusion, the cavalry heads straight for the Ottoman camps, while the remaining Vienna garrison sallied out of its defenses and joined in the assault. The Turkish army rapidly lost spirit after the failure of the sapping attempt, the denied invasion of the city, and the turning of the tide of battle against them. They accordingly retreated to the south and east.
In less than three hours after the cavalry attack, the Christian forces had won the battle and saved Vienna.
"Return from Vienna" by Józef Brandt, Polish-Lithuanian army returning with loot of the Ottoman forces The Turks lost about 15,000 men in the fighting, compared to approximately 4,000 for the Habsburg-Polish forces. On 25 December 1683, Kara Mustafa Pasha was executed in Belgrade by order of the commander of the Janissaries.
Although no one realized it at the time, the battle shaped the outcome of the entire war as well. The Ottomans fought on for another 16 years, lost control of Hungary and Transylvania in the process, before giving up, which was finalized by the Treaty of Karlowitz. The Battle of Vienna is seen by many historians as marking the beginning of the decline of the Ottoman Empire. The Battle also marked the historic end of Turkish expansion into southeastern Europe. Also, the behaviour of Louis XIV of France set the stage for centuries to come: German-speaking countries had to fight wars simultaneously in the West and the East.
While German troops were fighting for the Holy League, Louis ruthlessly used the occasion, before and after the battle of Vienna, to annex territories in western Europe, like Luxembourg, Alsace with Strasbourg etc. Due to the ongoing war against the Turks, Austria could not support the interest of German allies in the West. The biography of Ezechiel du Mas, Comte de Melac illustrates the devastastions of large parts of Southern Germany by France.
In honor of Sobieski, the Austrians had erected a church atop a hill of Kahlenberg, north of Vienna. Also, the train route from Vienna to Warsaw is named in Sobieski's honor. Legends related to the Battle of Vienna Several Culinary legends are related to the Battle of Vienna: One legend is that the croissant was invented in Vienna, either in 1683 or in an earlier siege in 1529, to celebrate the defeat of the Turkish siege of the city, as a reference to the crescents on the Turkish flags. Although this version is supported by the fact that croissants in French Language are referred to as Viennoiserie and the French popular belief that Vienna born Marie Antoinette introduced the pastry to France in 1770, there is no evidence that croissants existed before the 19th century.
Another legend from Vienna, made the first bagel as being a gift to King Jan Sobieski to commemorate the King's victory over the Turks that year. The baked-good was fashioned in the form of a stirrup, to commemorate the victorious charge by the Polish cavalry. The truth of this legend is more uncertain, as there is a reference in 1610 to a similar-sounding bread, which may or may not have been the bagel.
After the battle, the Austrians discovered many bags of coffee in the abandoned Turkish encampment. Using this captured stock, Franciszek Jerzy Kulczycki opened the third coffeehouse in Europe and the first in Vienna, where according to legend Kulczycki himself or Marco d'Aviano, the Capuchin friar and confidant of Leopold I, Holy Roman Emperor, added milk and honey to sweeten the bitter coffee, thereby inventing cappuccino.