On this Day, in 1757: Frederick the Great defeated the Habsburgs at the Battle of Prague

On May 6, 1757, Frederick the Great defeated the Austrian forces at the Battle of Prague during the Seven Years’ War, which marked the rise of Prussia to the status of a European great power and established the Austria–Prussia rivalry that would define German politics in Central Europe for the next century.

By ending the Bohemian Revolt, the Habsburg victory at the Battle of White Mountain in 1620 started the re-Catholicization of the Czech lands, which included Bohemia, Upper and Lower Lusatia, Moravia and Silesia, and ensured that the Crown of Bohemia would remain in Habsburg hands for nearly three hundred years.

Frederick of Prussia and the Austrian Succession

Two generations later, the newly crowned King Frederick II of Prussia, who had inherited from his devoutly Calvinist father a large and modernized Prussian army, began forming designs on Silesia, in which he held dynastic claims to several duchies. Besides its value as a source of tax revenue, industrial output and military recruits, the rich and populous province held great geostrategic importance.

The opportunity arose for Frederick to press his claims when Habsburg Emperor Charles VI died in October 1740 without a male heir. With the Pragmatic Sanction, Charles had earlier established as the successor to his hereditary titles his eldest daughter, Maria Theresa, who duly became ruler of Austria, as well as of the Bohemian and Hungarian lands within the Habsburg Monarchy.

But upon the Emperor’s death, the Pragmatic Sanction was promptly contested by Frederick of Prussia who, seeing in Austria’s female succession an opportune moment for the seizure of Silesia, argued that the decree did not apply to the province, which was held by the Habsburgs as a part of the imperial demesne rather than as a hereditary possession.

The First Silesian War

After ordering the mobilisation of the Prussian army, Frederick issued an ultimatum to Maria Theresa demanding the cession of Silesia, offering in return to guarantee all other Habsburg possessions against any attack, pay a large cash indemnity, acknowledge the Pragmatic Sanction, and give his vote as elector of Brandenburg to Maria Theresa’s husband, Duke Francis Stephen of Lorraine, in the forthcoming imperial election.

Not waiting for a response and without a declaration of war, Frederick led the Prussian troops across the lightly defended Silesian frontier, triggering the First Silesian War. By April 1741, Frederick had secured Prussian control of Silesia and, seeing Austria’s defeat, other powers were emboldened to attack the archduchy, widening the conflict into what would become the so-called War of the Austrian Succession.

As Bavaria, Saxony, France, Naples and Spain attacked Austria on multiple fronts during the succeeding months, Frederick began secret peace negotiations with Maria Theresa who, under British pressure, agreed to cede to Prussia the large majority of Silesia while Prussia agreed to remain neutral for the remainder of the ongoing war. Peace was finally signed at the Treaty of Berlin in July 1742.

The Second Silesian War

Peace with Prussia allowed the Austrians and their British–Hanoverian allies to reverse the gains made by the French and Bavarians. But as Austria recovered control of Bohemia, drove the French back across the Rhine, and occupied Bavaria, Frederick started to suspect that Maria Theresa planned to retake Silesia as soon as the war elsewhere was concluded. And in August 1744, he led soldiers across the frontier into Bohemia, beginning the Second Silesian War.

Frederick gathered his forces around Prague and tried to force a decisive engagement, but Austrian commander Otto Ferdinand von Traun focused on harassing the invaders’ supply lines, eventually forcing the Prussians to abandon Bohemia and retreat into Silesia. Meanwhile, Austria established a new “Quadruple Alliance” between Austria, Britain, Saxony and the Dutch Republic.

During the following months, Maria Theresa won the support of enough prince-electors to see her husband named Holy Roman Emperor Francis I in September 1745, achieving one of her major goals in the war. When peace was signed the following December, Maria Theresa acknowledged Prussian control of Silesia and Glatz, while Frederick recognised Francis I as Holy Roman Emperor.

The Diplomatic Revolution

But despite, Prussia’s withdrawal from the wider War of the Austrian Succession, Maria Theresa still refused to recognize Prussia’s sovereignty in Silesia, and Frederick in turn still declined to recognise Maria Theresa’s legitimacy as sovereign in the Bohemian lands under the Pragmatic Sanction. The underlying conflict over Silesia was unresolved, and both sides spent the years of peace making preparations for renewed conflict.

Prussia built and expanded fortifications at strategic points in Silesia, and the army began to reequip its artillery units with heavier guns. On the diplomatic front, Frederick, who by then had become known as Frederick the Great, worked to maintain Prussia’s alliance with France while easing British concerns over the security of the Electorate of Hanover and avoiding any provocations toward Russia, hoping to maintain the balance of power.

Fully intent on retaking the lost province and reasserting Austria’s hegemony in the Holy Roman Empire, Maria Theresa entered a defensive pact with Russia and began pursuing warmer relations with France. These efforts led Austria to abandon its alliance with Britain, who in turn entered a defensive alliance with Prussia, completing a diplomatic reordering of the European powers known as the Diplomatic Revolution.

The Seven Years’ War

As Austria, France and Russia formed a new anti-Prussian coalition, Frederick the Great once again chose to strike first and preemptively invaded neighbouring Saxony, a secret party to the coalition against him, beginning the Third Silesian War. As Austria’s and Prussia’s allies joined the fighting, the conflict quickly widened into what became known as the pan-European Seven Years’ War.

After having forced the surrender of the neighbouring Electorate, Frederick marched in four columns against the Bohemian capital of Prague and defeated the Austrian forces. But the victory was a costly one for Frederick. Given the high casualties he had suffered, he decided to lay siege rather than launch a direct assault on the walls of Prague.

But while Frederick’s army was busy besieging Prague, a second Austrian army arrived from Vienna and threatened the Prussians’ lines of supply. Without sufficient force to face a second army, Frederick decided to call back his army, effectively allowing the Austrians to reinforce Prague. The failure to take Bohemia meant the ruin of Frederick’s strategy, leaving him no prospect of a march on Vienna.

Frederick the Great and the rise of Prussia

The Battle of Prague marked a high-water mark for Frederick the Great, who would never hold so advantageous a position again and fight most of the remainder of the war on their own territory. Meanwhile, Prussia’s reversal in Bohemia coincided with the entry of new belligerents on the Austrian side, as a massive Russian force invaded East Prussia and took the fortress at Memel.

In January 1762, Austria was suddenly abandoned by its Russian ally upon the death of Empress Elizabeth. She was succeeded by the ardently pro-Prussian Peter III of Russia, who immediately recalled his armies from Berlin and Pomerania and made peace with Prussia, shifting the war in Prussia’s favour. With both sides nearing exhaustion, the Treaty of Hubertusburg signed in February 1763 returned to the status quo ante bellum, confirming Prussia’s control of Silesia.

Prussia’s unexpected victory over the Habsburg Monarchy marked its rise to the status of a European great power and the leading state of Protestant Germany. In addition, the Silesian Wars and their wider pan-European conflicts provoked a broad realignment in the European diplomatic system, establishing the Austria–Prussia rivalry that would define German politics in Central Europe for the next century.

And with Silesia now secured, Frederick the Great, who aimed to build a territorial bridge between Pomerania and his East Prussian province, soon began preparing the ground for the eventual partition of Poland.

Find out more about Central European history in our On this Day series.