The Silesian Wars (German: Schlesische Kriege) were a series of three wars fought in the mid-18th century between Prussia (under King Frederick the Great) and Austria (under Empress Maria Theresa) for control of Silesia, all three of which ended in Prussian victory. The First (1740–42) and Second (1744–45) Silesian Wars formed a part of the larger War of the Austrian Succession, while the Third Silesian War (1756–63) was one theater of the Seven Years' War.
Besides its value as a source of tax revenue, industrial output and military recruits, Silesia was strategically important to Prussia because its seizure "significantly blunted the capacity of Prussia's two chief foes—Austria and Russia—to meddle in Prussian affairs." Capture of Silesia, furthermore, prevented Augustus III of Poland from uniting his two realms of Poland and Saxony via a land bridge through Silesia. Prussia's repeated victories (and possession of Silesia) foreshadowed a wider Austro-Prussian struggle for hegemony over the German-speaking peoples that would culminate in the Austro-Prussian War of 1866.
Brandenburg–Prussia's claims in Silesia were based, in part, on a 1537 inheritance treaty between the Silesian duke Frederick II of Legnica and the Hohenzollern Prince-Elector Joachim II Hector of Brandenburg, whereby the Silesian duchies of Liegnitz, Wohlau and Brieg were to pass to the Electorate of Brandenburg if the Silesian Piasts should become extinct. At the time, the Habsburg King Ferdinand I of Bohemia (Silesia's legal overlord) immediately rejected the agreement; nevertheless, in 1675 the "Great Elector" Frederick William of Brandenburg laid claim to the Silesian principalities when, with the death of Duke George William of Liegnitz, the Piast line ended.
In 1603, Hohenzollern Elector Joachim III Frederick of Brandenburg also inherited the Silesian Duchy of Jägerndorf from his cousin, Margrave George Frederick of Brandenburg-Ansbach. After the Bohemian Revolt and the outbreak of the Thirty Years' War, however, the Catholic Holy Roman Emperor Ferdinand II confiscated the possessions of the Protestant Hohenzollerns in his Bohemian lands in 1621 after winning the Battle of White Mountain. The Electors of Brandenburg continued, nevertheless, to assert themselves as the legitimate rulers of Jägerndorf.
Brandenburg, however, was unable to enforce these dynastic territorial claims. In 1685, when Austria was engaged in the Great Turkish War, Emperor Leopold I gave Elector Frederick William immediate control of the Silesian exclave of Schwiebus in return for military support against the Turks and the surrender of the outstanding Hohenzollern claims in Silesia. However, after the accession of the Elector's son and successor, Frederick III of Brandenburg, the Emperor took back control of Schwiebus in 1694, asserting that the territory had only been personally assigned to the late Frederick William for life. Furious, Frederick III in turn reasserted the old Hohenzollern claims to Jägerndorf and the Silesian Piast heritage.
Forty-five years later, an opportunity arose for Brandenburg–Prussia to press these claims, when Habsburg Emperor Charles VI died in 1740 without a male heir. With the Pragmatic Sanction of 1713, Charles had established his eldest daughter as the successor to his hereditary titles, and upon his death she duly became ruler of the Archduchy of Austria, as well as of the Bohemian and Hungarian lands within the Habsburg Monarchy, as Archduchess Maria Theresa.:24 During Emperor Charles’s lifetime, the Pragmatic Sanction was generally acknowledged by the imperial states, but when he died it was promptly contested by several parties.:3100
The newly crowned King Frederick II of Prussia saw in Austria's succession crisis an opportune moment for the seizure of Silesia. Historians have downplayed the importance of his family's antique claims in the region in Frederick's decision to invade; the province was populous and industrialized, yet economic factors also seem not to have weighed heavily in the Prussian attack. Rather, geostrategic considerations probably played the leading role: Frederick believed (correctly) that Prince-Elector Frederick Augustus II of Saxony, who also ruled Poland in personal union, was interested in taking control of Silesia to connect his two realms into one contiguous territory that would almost surround Brandenburg.:192–193
After Emperor Charles's death on 20 October 1740, King Frederick quickly resolved to strike first; without a declaration of war, he led Prussian troops across the lightly defended Silesian frontier on 16 December, beginning the First Silesian War.:3 By the end of January 1741, almost the entirety of Silesia was under Prussian control, and the remaining Austrian strongholds of Glogau, Brieg and Neisse were besieged.:183 In late March, an Austrian force relieved the siege of Neisse, but the main Prussian force engaged and defeated it in the Battle of Mollwitz on 10 April, securing Prussian control of the region.:250
Seeing Austria's defeat at Mollwitz, other powers were emboldened to attack the beleaguered archduchy, widening the conflict into what would become the War of the Austrian Succession.:193–194 As Bavaria, France, Naples and Spain attacked Austria on multiple fronts during the summer, Frederick began secret peace negotiations with Maria Theresa; with British urging and mediation, on 9 October Austria and Prussia agreed to a secret armistice known as the Convention of Klein-Schnellendorf, under which Austria committed to eventually concede Lower Silesia in return for peace.
As Austria concentrated its forces against its other enemies and gained ground in the wider war, Frederick concluded that the Austrians did not intend to honor the Convention and concede territory in Silesia; so, to press Austria further, he repudiated the armistice and renewed offensive operations of his own. In December 1741, Prussian forces advanced into Moravia, occupying the capital at Olmütz, and besieged the fortress at Glatz on the edge of Bohemia. In February 1742, Frederick organized a joint advance through Moravia toward Vienna with the Saxons and French, but the allies were reluctant and uncooperative, and the campaign was abandoned in April, after which the Prussians withdrew into Bohemia and Upper Silesia.:4
An Austrian counteradvance into Bohemia engaged King Frederick's Prussians on 17 May and was narrowly defeated at the resulting Battle of Chotusitz. This defeat left Austria with no immediate means of driving its enemies out of Bohemia, and renewed bilateral peace talks began in Breslau. Under British pressure, Austria agreed to concede to Prussia the large majority of Silesia, along with the County of Glatz in Bohemia, while Austria would retain two small portions of the extreme southern end of Silesia, including the Duchy of Teschen and parts of the Duchies of Jägerndorf, Troppau, and Neisse. Prussia also agreed to take on some of Austria's debts, as well as committing to remain neutral for the remainder of the ongoing War of the Austrian Succession. This peace agreement was adopted with the Treaty of Breslau, which ended the First Silesian War on 11 June 1742, and later formalized in the Treaty of Berlin.
Peace with Prussia allowed the Austrians and their British–Hanoverian allies to reverse the gains made by the French and Bavarians in 1741. By the summer of 1743, Austria recovered control of Bohemia, drove the French back across the Rhine into Alsace, and occupied Bavaria, exiling the Bavarian Elector Charles Albert (now crowned Holy Roman Emperor Charles VII) to Frankfurt.:3103 In September 1743, Britain, Austria and Savoy–Sardinia concluded a new alliance under the Treaty of Worms that led Frederick to suspect that Maria Theresa meant to retake Silesia as soon as the war elsewhere was concluded. So, on 7 August 1744 Prussia declared its intervention in the Austrian war on behalf of Bavarian Emperor Charles, and Frederick led soldiers across the frontier into Bohemia on 15 August 1744, beginning the Second Silesian War.
After entering Bohemia, Prussian forces converged upon Prague by the beginning of September, seizing the city on 16 September. This new threat drew the Austrian army back from Alsace through Bavaria; the French, however, failed to harass and disrupt the Austrian redeployment,:215 so Austria's army was able to return to Bohemia quickly and at full strength, though it was forced to abandon control of Alsace and Bavaria. Frederick gathered his forces around Prague and tried repeatedly 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 Prague and Bohemia and retreat into Upper Silesia in November.
With the January 1745 Treaty of Warsaw, Austria established a new "Quadruple Alliance" among Austria, Britain, Saxony, and the Dutch Republic, followed by a secret offensive alliance between Austria and Saxony, which envisioned a territorial partition of Prussia. Meanwhile, Emperor Charles died on 20 January, destroying the rationale behind Frederick's alliance. These events combined to produce a major shift in the direction of the war in Germany. Austria renewed its offensive against Bavaria in March 1745, decisively defeating the Franco-Bavarian army at the 15 April Battle of Pfaffenhofen, and making peace with Maximilian III of Bavaria (the son of the late Emperor Charles) by the Treaty of Füssen on 22 April.:216
Having made peace with Bavaria, Austria began an invasion of Silesia. At the end of May, an Austrian–Saxon army crossed through the Giant Mountains into Silesia, only to be surprised and decisively defeated by Frederick in the Battle of Hohenfriedberg on 4 June. This defeat removed any immediate prospect of Austria's recovering Silesia.:84–88 The Prussians followed the retreating Austrian–Saxon army into Bohemia, encamping along the Elbe while Frederick pursued a peace agreement. During the summer, Maria Theresa won the support of enough prince-electors to see her husband named Holy Roman Emperor Francis I on 13 September in Frankfurt, achieving one of her major goals in the war.:3105
On 29 September the Austrians attacked Frederick's camp in Bohemia, resulting in the Battle of Soor, a solid Prussian victory, despite the Austrian surprise and superior numbers.:216 After this, the Prussians withdrew again into Upper Silesia for the winter. In November, Austria and Saxony prepared a surprise double invasion of Brandenburg, hoping together to seize Berlin and end the war outright.:216 Frederick was informed of these movements, however, and prepared troops in western Brandenburg and Lower Silesia. On 23 November, Frederick surprised the Austrian invaders in the Battle of Hennersdorf, confusing and scattering the larger Austrian force. Meanwhile, another Prussian army under Leopold I of Anhalt-Dessau advanced into western Saxony, attacking and destroying the main Saxon army in the Battle of Kesselsdorf on 15 December, after which the Prussians occupied Dresden.:3105
In Dresden the belligerents quickly negotiated a peace treaty, under which Maria Theresa recognized Prussian sovereignty in Silesia and Glatz, while Frederick acknowledged Francis I as Holy Roman Emperor and again committed to neutrality for the remainder of the War of the Austrian Succession.:3105 For its part in the Austrian alliance, Saxony was compelled to pay one million rixdollars in reparations to Prussia. The region's border were thus confirmed at status quo ante bellum, which had been Frederick's principal goal. This Treaty of Dresden was signed on 25 December 1745, ending the Second Silesian War between Austria, Saxony, and Prussia.
After Austria's defeat in the first two Silesian Wars, Maria Theresa was determined to rebuild her armed forces and form new alliances that could enable her to retake her lost province of Silesia. In 1756, these efforts led Austria to abandon its alliance with Britain in favor of a new Franco-Austrian alliance, prompting a diplomatic reordering of the European powers known as the Diplomatic Revolution. As Austria, France and Russia formed a new anti-Prussian coalition, King Frederick once again chose to strike first: on 29 August 1756, he preemptively invaded neighboring Saxony, beginning the Third Silesian War.:198–199
As Austria and Prussia's allies joined the fighting, the conflict quickly widened into what became the pan-European Seven Years' War. The Prussians initially made large advances in Saxony and Bohemia in late 1756, but in early 1757 an Austrian counterattack culminated in the major Austrian victory at the Battle of Kolín on 18 June, which drove the Prussians out of Bohemia entirely.:6 Meanwhile, Russian and Swedish invasions from the east and north divided Prussia's forces.
In the autumn of 1757 Austrian and French forces attempted to retake Saxony, only to experience a decisive defeat in the Battle of Rossbach on 5 November.:469–472 This battle secured Prussia's control of Saxony for the time, and the defeat greatly reduced French willingness to contribute further to the Silesian War.:254–255 Another Austrian army invaded Silesia, making significant progress until it was decisively defeated at the Battle of Leuthen on 5 December, after which the Prussians pursued the defeated Austrian army back to Bohemia and recovered control of all of Silesia.:161–167 The year ended with Prussia in control of both Silesia and Saxony.
In 1758, Russian forces advanced through East Prussia to threaten Brandenburg, fighting the Prussians to a draw on 25 August at the Battle of Zorndorf,:494–499 while an Austrian army advancing into Saxony made little progress, despite winning a substantial victory at the 14 October Battle of Hochkirch.:501–506
In 1759, a united Austrian and Russian advance into eastern Brandenburg culminated in a major Prussian defeat at the Battle of Kunersdorf on 12 August, but the victorious allies did not pursue the defeated Prussians or occupy the Prussian capital at Berlin.:250 During the retreat from Kunersdorf Frederick had thought the war lost, but his enemies' hesitation gave Prussia a second chance, a mistake that Frederick later termed the "Miracle of the House of Brandenburg.":419–420
Late 1759 saw a series of battles in Saxony, ending in Austria's occupation of Dresden and the southern portion of the electorate. In 1760, the Austrians advanced into Lower Silesia, where the Prussian and Austrian armies maneuvered against each other for some time before engaging in the Battle of Liegnitz on 15 August; the battle ended in a solid Prussian victory, disrupting the Austrians' advance and preserving Prussian control of Lower Silesia. In late 1760, the Russians and Austrians briefly occupied Berlin, and 1761 saw Russian advances in Pomerania and eastern Brandenburg which threatened a decisive end to the war the following year.:75
In January 1762, however, Austria was suddenly abandoned by its chief ally upon the death of Empress Elizabeth of Russia. 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. Peter was himself overthrown and assassinated that summer, but by then the war had again shifted in Prussia's favor.:204–205 Both sides were nearing exhaustion, and peace talks to end the wider Seven Years' War began in late 1762. In the end, negotiators agreed on a return to status quo ante bellum, confirming Prussia's control of Silesia in the February 1763 Treaty of Hubertusburg. Prussia also committed to support the election of Maria Theresa's son, Archduke Joseph, as Holy Roman Emperor.
Prussia emerged from the Silesian Wars as a new great power whose continental importance could no longer be disputed, and the leading power of Protestant Germany.:215–219 The kingdom had gained control of extensive new lands in Silesia, a densely industrialized region (for the time period) with a large population and substantial tax yields.:192 Frederick the Great’s personal reputation was enormously enhanced by his successes in the wars, as his debts to fortune (Russia’s volte-face after Elizabeth’s death) and to British financial support were soon forgotten, while the memories of his energetic leadership and tactical genius were strenuously kept alive.:90 His small kingdom had defeated the Habsburg Monarchy and defended its prize against Austria, Russia, Sweden, and (for a time) France, an accomplishment that appeared miraculous to contemporary observers.:200 After 1763, armies around the world sent their officers to Prussia to learn the secrets of the realm's outsize military power, making Prussia one of the most imitated states in Europe.:90
The defeats of the Silesian Wars cost the Habsburg Monarchy its wealthiest province, and capitulating to a lesser German prince significantly dented the House of Habsburg's prestige.:192,196 Still, by winning Prussia's support for the imperial elections of her husband (Emperor Francis I) and son (Emperor Joseph II), Maria Theresa ensured the continuation of her family's preeminence in the Holy Roman Empire. Defeat at the hands of an enemy so apparently inferior created a strong impetus for change and reform within the Austrian administration, resulting in a total realignment of Habsburg foreign policy (the "Diplomatic Revolution") and a series of military, educational and administrative reforms, many carried further by Emperor Joseph II.:212