Silesian Wars

The Silesian Wars (german: Schlesische Kriege, links=no) were three wars fought in the mid-18th century between Prussia (under King Frederick the Great) and Habsburg Austria (under Archduchess Maria Theresa) for control of the Central European region of Silesia (now in south-western Poland). The First (1740–1742) and Second (1744–1745) Silesian Wars formed parts of the wider War of the Austrian Succession, in which Prussia was a member of a coalition seeking territorial gain at Austria's expense. The Third Silesian War (1756–1763) was a theatre of the global Seven Years' War, in which Austria in turn led a coalition of powers aiming to seize Prussian territory.

No particular event triggered the wars. Prussia cited its centuries-old dynastic claims on parts of Silesia as a ''casus belli'', but ''Realpolitik'' and geostrategic factors also played a role in provoking the conflict. Maria Theresa's contested succession to the Habsburg monarchy under the Pragmatic Sanction of 1713 provided an opportunity for Prussia to strengthen itself relative to regional rivals such as Saxony and Bavaria.

All three wars are generally considered to have ended in Prussian victories, and the first resulted in Austria's cession of the majority of Silesia to Prussia. Prussia emerged from the Silesian Wars as a new European great power and the leading state of Protestant Germany, while Catholic Austria's defeat by a lesser German power significantly damaged the House of Habsburg's prestige. The conflict over Silesia foreshadowed a wider Austro-Prussian struggle for hegemony over the German-speaking peoples, which would later culminate in the Austro-Prussian War of 1866.

Context and causes

In the early 18th century Brandenburg–Prussia's ruling House of Hohenzollern held dynastic claims to several duchies within the Habsburg province of Silesia, a populous and prosperous region contiguous with Prussia's core territory in the Margraviate of Brandenburg. Besides its value as a source of tax revenue, industrial output and military recruits, Silesia held great geostrategic importance to multiple parties. The valley of the Upper Oder formed a natural military conduit between Brandenburg, the Kingdom of Bohemia and the Margraviate of Moravia, and whichever power held the territory could threaten its neighbours. Silesia also lay along the north-eastern frontier of the Holy Roman Empire, allowing its controller to limit the influence of the Polish–Lithuanian Commonwealth and of the Russian Empire within Germany.

Brandenburg–Prussia's claims

Brandenburg–Prussia's claims in Silesia were based, in part, on a 1537 inheritance treaty between the Silesian Piast Duke Frederick II of Legnica and the Hohenzollern Prince-Elector JoachimII Hector of Brandenburg, whereby the Silesian Duchies of Liegnitz, Wohlau and Brieg were to pass to the Hohenzollerns of Brandenburg should the Piast dynasty in Silesia become extinct. At the time, the Habsburg King FerdinandI of Bohemia (Silesia's feudal overlord) rejected the agreement and pressed the Hohenzollerns to repudiate it. In 1603, Hohenzollern Elector JoachimIII Frederick of Brandenburg separately inherited the Silesian Duchy of Jägerndorf from his cousin, Margrave George Frederick of Brandenburg-Ansbach, and installed his second son, Johann Georg, as duke.

In the 1618 Bohemian Revolt and the ensuing Thirty Years' War, Johann Georg joined the Silesian estates in revolt against the Catholic Holy Roman Emperor FerdinandII. After the Catholic victory in the 1621 Battle of White Mountain, the Emperor confiscated Johann Georg's duchy and refused to return it to his heirs after his death, but the Hohenzollerns of Brandenburg continued to assert themselves as the legitimate rulers of Jägerndorf. In 1675 the "Great Elector" Frederick William of Brandenburg laid claim to Liegnitz, Wohlau and Brieg when the Silesian Piast line ended with the death of Duke George William of Liegnitz, but the Habsburg Emperor disregarded the Hohenzollern claims, and the lands escheated to the crown.

In 1685, when Austria was engaged in the Great Turkish War, Emperor LeopoldI gave Great 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. After the accession of the Great Elector's son and successor, FrederickIII of Brandenburg, the Emperor took back control of Schwiebus in 1694, claiming that the territory had only been personally assigned to the late Great Elector for life. As a young prince, FrederickIII had secretly agreed to this repossession in return for Leopold's payment of some of his debts, but as monarch he repudiated the agreement and reasserted the old Hohenzollern claims to Jägerndorf and the Silesian Piast heritage.

Austrian succession

Two generations later, the newly crowned Hohenzollern King Frederick II of Prussia formed designs on Silesia soon after succeeding to the throne in May 1740. Frederick judged that his dynasty's claims were credible, and he had inherited from his father a large and well trained Prussian army and a healthy royal treasury. Austria was in financial distress, and its army had not been reinforced or reformed after an ignominious performance in the 1737–1739 Austro-Turkish War. The European strategic situation was favourable for an attack on Austria, as Britain and France were occupying each other's attentions in the War of Jenkins' Ear, and Sweden was moving toward war with Russia. The Electors of Bavaria and Saxony also had claims against Austria and seemed likely to join in the attack. Though the Hohenzollerns' dynastic claims provided a legalistic ''casus belli'', considerations of ''Realpolitik'' and geostrategy played the leading role in provoking the war.

An opportunity arose for Brandenburg–Prussia to press its claims when Habsburg Holy Roman Emperor CharlesVI died in October 1740 without a male heir. With the Pragmatic Sanction of 1713, Charles had established his eldest daughter, Maria Theresa, as the successor to his hereditary titles. Upon his death she duly became ruler of Austria, as well as of the Bohemian and Hungarian lands within the Habsburg monarchy. During Emperor Charles's lifetime the Pragmatic Sanction was generally acknowledged by the imperial states, but when he died it was promptly contested by Prussia, Bavaria and Saxony.

Moves toward war

Frederick saw in Austria's female succession an opportune moment for the seizure of Silesia, calling it "the signal for the complete transformation of the old political system" in a 1740 letter to Voltaire. He argued that the Pragmatic Sanction did not apply to Silesia, which was held by the Habsburgs as a part of the imperial demesne rather than as a hereditary possession. Frederick also argued that his father, King Frederick WilliamI, had assented to the Sanction in return for assurances of Austrian support for Hohenzollern claims on the Rhenish Duchies of Jülich and Berg, which had not yet materialised.

Meanwhile, Prince-Elector Charles Albert of Bavaria and Prince-Elector Frederick AugustusII of Saxony had each married one of Maria Theresa's older cousins from a senior branch of the House of Habsburg, and they used these connections to justify claims to Habsburg territory in the absence of a male heir. Frederick Augustus, who ruled Poland in personal union, was especially interested in gaining control of Silesia to connect his two realms into one contiguous territory (which would nearly surround Brandenburg); Frederick's concern to prevent this outcome contributed to his haste in moving against Austria when the contested succession provided an opportunity.

Methods and technologies

European warfare in the early modern period was characterised by the widespread adoption of firearms in combination with more traditional bladed weapons. 18th-century European armies were built around units of massed infantry armed with smoothbore flintlock muskets and bayonets. Cavalrymen were equipped with sabres and pistols or carbines; light cavalry were used principally for reconnaissance, screening and tactical communications, while heavy cavalry were used as tactical reserves and deployed for shock attacks. Smoothbore artillery provided fire support and played the leading role in siege warfare. Strategic warfare in this period centred around control of key fortifications positioned so as to command the surrounding regions and roads, lengthy sieges being a common feature of armed conflict. Decisive field battles were relatively rare, though they played a larger part in Frederick's theory of warfare than was typical among his contemporary rivals.

The Silesian Wars, like most European wars of the 18th century, were fought as so-called cabinet wars in which disciplined regular armies were equipped and supplied by the state to conduct warfare on behalf of the sovereign's interests. Occupied enemy territories were regularly taxed and extorted for funds, but large-scale atrocities against civilian populations were rare compared with conflicts in the previous century. Military logistics was the decisive factor in many wars, as armies had grown too large to support themselves on prolonged campaigns by foraging and plunder alone. Military supplies were stored in centralised magazines and distributed by baggage trains that were highly vulnerable to enemy raids. Armies were generally unable to sustain combat operations during winter and normally established winter quarters in the cold season, resuming their campaigns with the return of spring.

First Silesian War

After Emperor Charles's death on 20 October 1740, Frederick quickly resolved to strike first; on 8November he ordered the mobilisation of the Prussian army, and on 11 December he issued an ultimatum to Maria Theresa demanding the cession of Silesia. In return, he offered 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 to replace the deceased Charles.

Not waiting for a response and without a declaration of war, he led Prussian troops across the lightly defended Silesian frontier on 16 December, beginning the First Silesian War. 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 on 10 April, securing Prussian control of the region.

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. As Bavaria, Saxony, France, Naples and Spain attacked Austria on multiple fronts during the succeeding months, Frederick began secret peace negotiations with Maria Theresa, with British urging and mediation; on 9October 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 honour the Convention and concede territory in Silesia. 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 January 1742 Duke Charles Albert of Bavaria won the 1742 Imperial election and became Holy Roman Emperor. In February Frederick organised a joint advance through Moravia toward Vienna with the Saxons and French, but Prussia's allies were reluctant and uncooperative, and the campaign was abandoned in April, after which the Prussians withdrew into Bohemia and Upper Silesia.

An Austrian counter-advance into Bohemia engaged 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 peace talks with Prussia began in Breslau. Under British pressure, Austria agreed to cede 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, which ended the First Silesian War on 11 June 1742, and was later formalised in the Treaty of Berlin.

Second Silesian War

Peace with Prussia allowed the Austrians and their British–Hanoverian allies to reverse the gains made by the French and Bavarians in 1741. By mid 1743 Austria recovered control of Bohemia, drove the French back across the Rhine, and occupied Bavaria. In September 1743 Britain, Austria and Savoy–Sardinia concluded a new alliance under the Treaty of Worms, which led Frederick to suspect that Maria Theresa meant to retake Silesia as soon as the war elsewhere was concluded. So, on 7August 1744 Prussia declared its intervention in the ongoing conflict on behalf of Emperor Charles Albert, and Frederick led soldiers across the frontier into Bohemia on 15 August, beginning the Second Silesian War.

Prussian forces converged upon Prague, seizing the city on 16 September, and this new threat drew the Austrian army back from France through Bavaria. The French failed to harass and disrupt the Austrian redeployment, so Austria's army was able to return to Bohemia quickly and at full strength. 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 Upper Silesia in November.

With the January 1745 Treaty of Warsaw, Austria established a new "Quadruple Alliance" between Austria, Britain, Saxony and the Dutch Republic. Meanwhile, Emperor Charles Albert died on 20 January, destroying the rationale behind Frederick's alliance. 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 MaximilianIII of Bavaria (the son of the late Emperor Charles Albert) by the Treaty of Füssen on 22 April.

Having defeated 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 4June, removing any immediate prospect of Austria recovering Silesia. The Prussians followed the retreating Austrian–Saxon army into Bohemia, encamping along the Elbe while Frederick pursued a peace agreement. During the following months Maria Theresa won the support of enough prince-electors to see her husband named Holy Roman Emperor FrancisI on 13 September in Frankfurt, achieving one of her major goals in the war.

On 29 September the Austrians attacked Frederick's camp in Bohemia, resulting in a Prussian victory at the Battle of Soor, despite the Austrian surprise and superior numbers. Soon low supplies forced the Prussians to withdraw into Upper Silesia for the winter. In November Austria and Saxony prepared a surprise double invasion of Brandenburg, hoping to seize Berlin and end the war outright. 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 LeopoldI 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.

In Dresden the belligerents quickly negotiated a peace treaty, under which Maria Theresa acknowledged Prussian control of Silesia and Glatz, while Frederick recognised FrancisI as Holy Roman Emperor and again committed to neutrality for the remainder of the War of the Austrian Succession. For its part in the Austrian alliance, Saxony was compelled to pay one million rixdollars in reparations to Prussia. The region's borders were thus confirmed at the '' status quo ante bellum'', which had been Prussia's principal goal. This Treaty of Dresden was signed on 25 December 1745, ending the Second Silesian War between Austria, Saxony and Prussia.

Interbellum

After Prussia's withdrawal the wider War of the Austrian Succession continued for another two years, ending with the Treaty of Aix-la-Chapelle in 1748. Despite the commitments made under the Treaty of Dresden, Maria Theresa still refused to give the Holy Roman Empire's recognition of 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. The crown established Prussia's first central bank, and the treasury gathered its surpluses into a growing war chest throughout the peace. In diplomacy, Frederick worked to maintain Prussia's alliance with France while easing British concerns over the security of the Electorate of Hanover, which British King GeorgeII also ruled in personal union. By these means, and by avoiding any provocations toward Russia, he hoped to manage the Austrian threat and preserve the balance of power.

After the Treaty of Dresden, Maria Theresa initiated a wave of so-called Theresian reforms of Austria's administration and military, as well as ordering a review of her government's diplomatic policy. Her Chancellor Friedrich Wilhelm von Haugwitz oversaw a dramatic reform of the realm's systems of taxation, which funded a significant expansion of Austria's field armies. Field Marshal Leopold Joseph von Daun standardised the army's equipment and professionalised its training, drawing on the Prussian model. In 1746 Maria Theresa entered a defensive pact with Empress Elizabeth of Russia that aligned their two realms against Prussia. Beginning in 1753 Foreign Minister Wenzel Anton von Kaunitz pursued warmer relations with Austria's traditional rival, the Kingdom of France. In 1756 these efforts led Austria to abandon its alliance with Britain in favour of a new Franco-Austrian alliance, while Prussia and Britain entered a defensive alliance