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.

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.

[5] 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.

[8] As a young prince, Frederick III had secretly agreed to this repossession in return for Leopold's payment of some of his debts,[9] but as monarch he repudiated the agreement and reasserted the old Hohenzollern claims to Jägerndorf and the Silesian Piast heritage.

[1] Though the Hohenzollerns' dynastic claims provided a legalistic casus belli, considerations of Realpolitik and geostrategy played the leading role in provoking the war.

[15] During Emperor Charles's lifetime the Pragmatic Sanction was generally acknowledged by the imperial estates, but when he died it was promptly contested by Prussia, Bavaria and Saxony.

[16] 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.

[19] 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.

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.

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

[23] In return, he offered to guarantee all other Habsburg possessions against any attack, pay a large cash indemnity,[24] 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.

[29] 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.

[31] 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.

[46] During the following months 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.

[47] In Dresden the belligerents quickly negotiated a peace treaty, under which Maria Theresa acknowledged Prussian control of Silesia and Glatz, while Frederick recognised Francis I as Holy Roman Emperor and again committed to neutrality for the remainder of the War of the Austrian Succession.

[56] 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.

[57] 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.

[60] Beginning in 1753 Foreign Minister Wenzel Anton von Kaunitz pursued warmer relations with Austria's traditional rival, the Kingdom of France.

[72] Over the winter a combined Prussian-Hanoverian army launched a series of offensives that eventually drove the French out of Westphalia and across the Rhine, securing Prussia's western flank for the duration of the war.

Austrians intercepted and destroyed a major Prussian supply convoy on 30 June in the Battle of Domstadtl, and the invaders abandoned the siege, retreating into Upper Silesia.

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 by the Treaty of Saint Petersburg on 5 May.

In the end, negotiators agreed again on a return to the status quo ante bellum, confirming Prussia's control of Silesia in the Treaty of Hubertusburg in February 1763.

These conflicts provoked a broad realignment in the European diplomatic system of the time, establishing an Austria–Prussia rivalry that would define German politics for a century until after the Austro-Prussian War of 1866.

[92] The kingdom had gained some 35,000 square kilometres (14,000 sq mi) of new territory and around a million new subjects in Glatz and Silesia,[93] a populous and densely industrialised region that would contribute substantial manpower and taxes to the Prussian state.

[96] His debts to fortune (Russia's about-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 promoted.

[97] His small kingdom had defeated the Habsburg monarchy and defended its prize against Austria, Britain, Saxony, Russia, Sweden, and France, an accomplishment that appeared miraculous to contemporary observers.

[98] Though sometimes depicted as a key moment in Prussia's rise to greatness, the wars nonetheless left the kingdom's economy and population devastated, and much of the remainder of Frederick's reign was spent repairing the damage.

[99] The repeated currency devaluations imposed to finance the conflicts led to rapid inflation and great economic disruption in Prussia (and in occupied Saxony).

[104] Still, by winning Prussia's support for the Imperial elections of her husband and son, Maria Theresa ensured the continuation of her family's titular pre-eminence in the Holy Roman Empire, though this was far less than she had hoped for.