Following the realignment of traditional alliances in the so-called 1756 Diplomatic Revolution, Prussia allied with Britain, while the long running French–Habsburg rivalry ended when Austria signed a treaty with France.

In the early 1750s the French began constructing a chain of forts in the Ohio River Valley to assert their claim and shield the Native American population from increasing British influence.

Even so, France concluded a defensive alliance with Prussia in 1747, and the Duke of Newcastle, British secretary of state in the 1743-1754 ministry of his brother Henry Pelham, deemed the maintenance of the Anglo-Austrian alignment after 1748 as essential.

On 2 June 1746, Austria and Russia had signed the 1746 Treaty of Saint Petersburg [ru],[18] a defensive alliance that covered their own territories and Poland against attack by Prussia or by the Ottoman Empire.

Vienna and Saint Petersburg also agreed to a secret clause that promised the restoration of Silesia and of the countship of Glatz (now Kłodzko, Poland) to Austria in the event of hostilities with Prussia.

Their real desire, however, was to destroy Frederick's power altogether, reducing his sway to his Electorate of Brandenburg and giving East Prussia to Poland in exchange for the cession of the Polish Duchy of Courland to Russia.

The Hanoverian King George II of Great Britain was passionately devoted to his family's continental holdings, but his commitments in Germany were counterbalanced by the demands of the British colonies overseas.

Unbeknownst to his foreign minister, Louis had established a network of agents throughout Europe with the goal of pursuing personal political objectives that were often at odds with France's publicly stated policies.

In the attempt to satisfy Austria at the time, in the 1764 imperial election Britain gave the Hanoverian electoral vote to support the candidacy of Maria Theresa's son, Joseph II, as the Holy Roman Emperor (r. 1765–1790), much to the dismay of Frederick and Prussia.

[20] Strategic warfare in this period centred around control of key fortifications positioned so as to command the surrounding regions and roads, with lengthy sieges a common feature of armed conflict.

Severely underestimating a reformed Austrian army under General Maximilian Ulysses Browne, he found himself outmanoeuvred and outgunned, and at one point in the confusion even ordered his troops to fire on retreating Prussian cavalry.

This problem was compounded when the main Hanoverian army under Cumberland, which include Hesse-Kassel and Brunswick troops, was defeated at the Battle of Hastenbeck and forced to surrender entirely at the Convention of Klosterzeven following a French Invasion of Hanover.

The new strategy emphasised both Newcastle's commitment to British involvement on the continent, particularly in defence of its German possessions, and Pitt's determination to use naval power to seize French colonies around the globe.

Ferdinand's Hanoverian army, supplemented by some Prussian troops, had succeeded in driving the French from Hanover and Westphalia and re-captured the port of Emden in March 1758 before crossing the Rhine with his own forces, which caused alarm in France.

Her Prussophile successor, Peter III, at once ended the Russian occupation of East Prussia and Pomerania (see: the Treaty of Saint Petersburg) and mediated Frederick's truce with Sweden.

[44] British subsidies had been stopped by the new prime minister, John Stuart (Lord Bute), and the Russian emperor had been overthrown by his wife, Catherine, who ended Russia's alliance with Prussia and withdrew from the war.

While Frederick still had a significant amount of money left from the prior British subsidies, he hoped to use it to restore his kingdom's prosperity in peacetime; in any case, Prussia's population was so depleted that he could not sustain another long campaign.

[93][page needed] Great Britain planned a "descent" (an amphibious demonstration or raid) on Rochefort, a joint operation to overrun the town and burn shipping in the Charente.

When François Gaston de Lévis sent 1,000 soldiers to reinforce Montcalm's struggling troops, the British were pinned down in the brush by intense French musket fire and they were forced to retreat.

Under the Treaty of Paris, Spain had to return to Portugal the settlement of Colonia do Sacramento, while the vast and rich territory of the so-called "Continent of S. Peter" (the present-day Brazilian state of Rio Grande do Sul) would be retaken from the Spanish army during the undeclared Hispano-Portuguese war of 1763–1777.

[119][120] The war contributed also to a decision to improve communications between Buenos Aires and Lima resulting in the establishment of a series of mountain shelters in the high Andes called Casuchas del Rey.

The war began in Southern India but spread into Bengal, where British forces under Robert Clive recaptured Calcutta from the Nawab Siraj ud-Daulah, a French ally, and ousted him from his throne at the Battle of Plassey in 1757.

The previous wars had cost the empire greatly, both in terms of resources and finance, they were facing rebellions from nationalistic uprisings, notably from the Beyliks, and Persia had been reunited under Karim Khan Zand.

Tsar Peter III had desired on reclaiming his title of Duke of Holstein-Gottorp, whose lands were being overseen by the current king of Denmark-Norway, Frederick V, and was prepared to attack Denmark–Norway in order to do this.

The exchanges suited the British as well, as their own West Indian islands already supplied ample sugar, and, with the acquisition of New France and Florida, they now controlled all of North America east of the Mississippi.

Frederick the Great's personal reputation was enormously enhanced, as his debt to fortune (Russia's betrayal after Elizabeth's death) and to British financial support were soon forgotten, while the memory of his energy and his military genius was strenuously kept alive.

[139] Still, the fact that the Russians proved capable of defeating in battle the army of a "first-rate" European power on its own soil despite the often indifferent quality of their generals improved Russia's standing in Europe.

[144] King George III's Proclamation of 1763, which forbade white settlement beyond the crest of the Appalachians, was intended to appease the Indians but led to considerable outrage in the Thirteen Colonies, whose inhabitants were eager to acquire native lands.

But after her surprising grand success against a coalition of great powers, European states such as Austria, the Dutch Republic, Sweden, Denmark–Norway, the Ottoman Empire and Russia, now saw Britain as a greater threat than France and did not join with it, while the Prussians were angered by what they considered a British betrayal in 1762.

[147] It would require a greater philosopher and historian than I am to explain the causes of the famous Seven Years' War in which Europe was engaged; and, indeed, its origin has always appeared to me to be so complicated, and the books written about it so amazingly hard to understand, that I have seldom been much wiser at the end of a chapter than at the beginning, and so shall not trouble my reader with any personal disquisitions concerning the matter.