Why did Suleiman turn back from Vienna in 1529, and what came next?
TL;DR — Suleiman reached Vienna on September 26, 1529, and gave up after three weeks as winter came early; he then took Baghdad, wrote law, and built the Süleymaniye.
Suleiman I camped outside Vienna on September 26, 1529, and lifted the siege after three weeks when an early winter and heavy losses made the attack pointless. The Habsburg history portal Die Welt der Habsburger gives those dates and that cause. The western frontier then settled into a costly stalemate. Suleiman turned east and took Baghdad in the campaign of 1534 to 1535. At home he issued the dynastic law that gave him his Turkish name, Kanuni, and commissioned the Süleymaniye complex from the architect Sinan. He died on campaign at Szigetvár in Hungary in September 1566.
Quick facts
- When
- fall of 1520 (accession, after Selim I died on September 21) · August 29, 1526 (Mohács) · September 26, 1529 (camp outside Vienna) · 1535 (withdrawal from Mesopotamia except Baghdad) · 1550 to 1557 (Süleymaniye built) · September 1566 (death at Szigetvár)
- Where
- Vienna, the Habsburg capital on the Danube; Buda and Mohács in Hungary; Baghdad in what is now Iraq; Constantinople, the Ottoman capital, now Istanbul
- Who
- Sultan Suleiman I; the Habsburg brothers Ferdinand and Charles V; Count Niklas von Salm, who held Vienna; the grand vizier Rüstem; Hürrem; the architect Sinan; the ambassador Ogier Ghiselin de Busbecq
- Outcome
- Vienna held; Hungary split three ways for 150 years; the Ottomans kept Baghdad; Suleiman built the Süleymaniye and was remembered as Kanuni, the lawgiver; he died on his last campaign in 1566
The young sultan's first campaigns, 1520 to 1526
Suleiman became sultan in the fall of 1520, when his father Selim I died near Çorlu on September 21. Selim had spent his reign fighting Safavid Persia; the son, as the Encyclopaedia Iranica puts it, focused on the West, and aimed the army at targets his father had ignored.
Belgrade, then a Hungarian frontier town, fell in 1521. Rhodes was taken from the Knights Hospitaller in 1522, a conquest the Persian shah’s embassy congratulated him on in September 1523. On August 29, 1526, at Mohács in southern Hungary, an Ottoman army that the Habsburg portal puts at 60,000 destroyed a Hungarian force of 25,000 and killed King Louis II. In the same years Suleiman began his lifelong relationship with a concubine named Hürrem.
Mohács handed the Ottomans a new enemy. Louis’s brother-in-law, Ferdinand of Habsburg, was elected king of Bohemia and Hungary, and a rival Hungarian claimant, John Zápolya, took the Ottoman side.
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Vienna, autumn 1529, and the stalemate after
In the summer of 1529 Suleiman left Adrianople, now Edirne, with an army that the Habsburg portal counts at 150,000 men and camp followers. Buda fell on September 8. On September 26 the sultan pitched camp at Kaiserebersdorf, southeast of Vienna’s walls, which still dated largely from the 13th century. Inside stood about 12,000 mercenaries under Count Niklas von Salm and 5,000 imperial troops under the count palatine Philip, who had arrived a day ahead of the sultan.
Several assaults failed, and after three weeks the Ottomans withdrew. Stephan Gruber, writing for the portal, puts the deaths on the winter march back toward Constantinople at some 30,000, a figure he presents as an estimate. Martin Mutschlechner, on the same site, attributes the withdrawal to “the unexpectedly early onset of winter that year.” The Ottoman side is thinner in the sources cited below.
Ogier Ghiselin de Busbecq, the Holy Roman Emperor’s ambassador at Suleiman’s court from 1555 to 1562, described in his letters how an Ottoman army held back its grain at the start of a campaign, because the troops knew that when the season ended they would retreat across country the enemy had stripped bare. He wrote of campaigns in general, and it fits the Austrian account of 1529.
The war went on. In 1533 Ferdinand bought a ceasefire with a payment, and Buda passed under direct Ottoman rule in 1541. For 150 years, according to Gruber, Hungary stayed split three ways: a Habsburg northwest, an Ottoman center, and a Transylvania under Ottoman sovereignty. Vienna rebuilt its walls.
The eastern front: Baghdad, 1534 to 1535
Colin Paul Mitchell, in the Encyclopaedia Iranica entry on Shah Tahmasp, wrote that news of a large Ottoman invasion led by the sultan in person reached the shah in the spring of 1534, and that Tahmasp’s brother Sam Mirza had been in secret correspondence with Suleiman to be placed on the throne at Tabriz. The plan collapsed. In 1535 Suleiman withdrew from Mesopotamia, keeping Baghdad. A second invasion followed in 1548, again at a Safavid prince’s invitation, and peace came at Amasya on May 29, 1555.
The lawgiver: kanun, the Süleymaniye and Sinan
By the 1540s Suleiman had a stalemate on both fronts. His answer was administration and building. Turkish speakers still know him as Kanuni Sultan Süleyman, the name Turkey’s Ministry of Culture portal uses for the man who ordered the Süleymaniye; kanun is the sultan’s own law, as distinct from the religious law.
The Süleymaniye complex in Constantinople, designed by the chief architect Sinan and built from 1550 to 1557 according to UNESCO, which lists it within the Historic Areas of Istanbul, was the center of that program. The Turkish culture portal gives the building years as 1551 to 1558 and calls it the work of Sinan’s journeyman years; its four minarets, it says, mark Suleiman as the fourth sultan since the conquest of Istanbul, and their ten balconies mark him as the tenth Ottoman sultan.
Busbecq saw the system from inside. “No distinction is attached to birth among the Turks,” he wrote in the 1881 Forster and Daniell translation of his letters; the highest officers, he added, were mostly the sons of shepherds and herdsmen, and the sultan kept 12,000 Janissaries at full strength. Kaya Şahin, in a 2013 Cambridge study, argues that this empire competed directly with the Habsburgs and Safavids as an imperial culture.
The court: Rüstem, Hürrem and the sons
Busbecq, who knew the court, wrote that Suleiman broke with the custom of his predecessors and made Hürrem, whom he calls Roxolana, a lawful wife with a dowry; that the grand vizier Rüstem was the sultan’s son-in-law; and that the Turks blamed Rüstem’s slanders and Hürrem’s spells for the estrangement that ended with the eldest son, Mustafa, strangled in his father’s camp. The 1881 editors of the letters date that death to the Persian campaign of 1553. A few years later another son, Bayezid, rebelled, lost, and fled to Tahmasp’s court, in 1562 according to the Encyclopaedia Iranica; Busbecq described how Suleiman’s envoy bought him back from the shah and strangled him with a bowstring, and how his four sons died with him.
The end at Szigetvár, 1566
In 1566 Suleiman marched into Hungary once more, against a Habsburg emperor, Maximilian II, who according to the Habsburg portal had more than 80,000 soldiers strung along almost a thousand kilometers of frontier. Suleiman died in September 1566 in front of the fortress town of Szigetvár. The Ottomans took the town; the Habsburgs failed to win it back, and about 40 per cent of the old kingdom of Hungary stayed under Ottoman rule.
Vienna in 1529 was where the campaign season ran out. What Suleiman built after it, in Baghdad, in law and in stone on the Constantinople skyline, outlasted every frontier he failed to move.
Key facts
- Suleiman became sultan in the fall of 1520, after Selim I died on September 21, and reigned until his death at Szigetvár in September 1566 (Encyclopaedia Iranica; Habsburg portal).
- At Mohács on August 29, 1526, an Ottoman army of about 60,000 defeated 25,000 Hungarians and killed Louis II (Habsburg portal).
- The 1529 siege of Vienna ran three weeks from September 26; the city held with about 17,000 defenders under Niklas von Salm and Philip of the Rhine.
- Gruber estimates 30,000 Ottoman deaths on the winter retreat; Mutschlechner attributes the withdrawal to an early winter.
- Suleiman invaded Safavid Iran in 1534 and withdrew in 1535, keeping Baghdad (Encyclopaedia Iranica).
- The Süleymaniye complex, by Sinan, was built from 1550 to 1557 (UNESCO).
- Busbecq counted 12,000 Janissaries at full strength in the 1550s.
FAQ
Why did the Ottomans leave Vienna in 1529?
The Austrian historians on the Habsburg portal give an early winter and heavy losses after three weeks of failed assaults.
What does Kanuni mean?
It is the name later authors gave Suleiman, meaning the formulator of dynastic law (kanun), for his effort to set that law beside the Sharia.
How did Suleiman die?
On campaign, in September 1566, outside the fortress town of Szigetvár in Hungary, which his army took; the Habsburgs never won it back.
Sources
- Encyclopaedia Iranica — "Ottoman-Persian Relations i. Under Sultan Selim I and Shah Esmāʿil I": Selim I's death on September 21, 1520, Süleymān's accession (r. 1520–66), the conquest of Rhodes.
- Die Welt der Habsburger (Schönbrunn Group) — "(Minor) hostilities along the Military Frontier": Suleiman's death at Szigetvár in September 1566; about 40 per cent of old Hungary under Ottoman rule.
- Project Gutenberg — The Life and Letters of Ogier Ghiselin de Busbecq, ed. C. T. Forster and F. H. B. Daniell (1881), vols. I–II: Roostem (Rüstem), Roxolana, the death of Mustapha, the flight and strangling of Bajazet.
- Türkiye Kültür Portalı (Ministry of Culture and Tourism) — "Süleymaniye Camii": built 1551–1558 by order of Kanuni Sultan Süleyman, Sinan's work.
- Die Welt der Habsburger (Schönbrunn Group) — Stephan Gruber, "'The Turk' at the gates of Vienna: Episode 1."
- Die Welt der Habsburger (Schönbrunn Group) — Stephan Gruber, "A new great power in south-east Europe: the Ottoman Empire."
- Die Welt der Habsburger (Schönbrunn Group) — Martin Mutschlechner, "Ferdinand I: new crowns for the Habsburgs."
- Internet Modern History Sourcebook, Fordham University — Ogier Ghiselin de Busbecq, The Turkish Letters, 1555–1562, from C. T. Forster and F. H. B. Daniell, eds., The Life and Letters of Ogier Ghiselin de Busbecq, vol. 1 (London, 1881).
- Encyclopaedia Iranica — Colin Paul Mitchell, "Ṭahmāsp I" (July 15, 2009).
- UNESCO World Heritage Centre — "Historic Areas of Istanbul," World Heritage List no. 356.
- Cambridge University Press — Kaya Şahin, Empire and Power in the Reign of Süleyman (2013), publisher's description.
Cite this article
- APA
- Song Letter. (2026, September 20). Why did Suleiman turn back from Vienna in 1529, and what came next? Our Earth's History. https://ourearthshistory.com/west-asia/early-modern/suleiman-vienna-1529-and-the-law/
- Chicago
- Song Letter. “Why did Suleiman turn back from Vienna in 1529, and what came next?” Our Earth's History, September 20, 2026. https://ourearthshistory.com/west-asia/early-modern/suleiman-vienna-1529-and-the-law/.
- MLA
- Song Letter. “Why did Suleiman turn back from Vienna in 1529, and what came next?” Our Earth's History, 20 Sep. 2026, https://ourearthshistory.com/west-asia/early-modern/suleiman-vienna-1529-and-the-law/.
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