The Seven Years' War, 1756 to 1763, was a global war fought by numerous great powers, primarily in Europe, with significant subsidiary campaigns in North America and the Indian subcontinent. The primary warring states were Great Britain and Prussia fighting against France and Austria, with other countries joining these coalitions: Portugal, Spain, Sweden, and Russia, plus Saxony and many other minor states of the Holy Roman Empire. Related conflicts include the Third Silesian War, French and Indian War, Third Carnatic War, Anglo-Spanish War (1762–1763), and Spanish–Portuguese War.
Although the War of the Austrian Succession ended with the Treaty of Aix-la-Chapelle (1748), none of the signatories were happy with the terms, and it was generally viewed as a temporary armistice. It led to a strategic realignment known as the Diplomatic Revolution that ended the long-running rivalry between Austria and France. The two declared war on Britain after signing the Treaty of Versailles in 1756, with a second agreement in 1757 bringing Prussia into the war on the side of Britain.
Spain became a French ally in 1762, unsuccessfully invading Portugal, and losing Havana and Manila to Britain. Although these were returned under the Treaty of Paris in 1763, France lost its possessions in North America, while Britain established its commercial dominance in India.
The conflict in Europe centred on Austrian attempts to recover Silesia, and ended with the Treaty of Hubertusburg in 1763. This confirmed Prussian occupation of Silesia and its status as a great power, challenging Austria for dominance within Germany and altering the European balance of power.
Background
In North America
The boundary between British and French possessions in North America was largely undefined in the 1750s. France had long claimed the entire Mississippi River basin. This was disputed by Britain. 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.
The British settlers along the coast were upset that French troops would now be close to the western borders of their colonies. They felt the French would encourage their tribal allies among the North American natives to attack them. Also, the British settlers wanted access to the fertile land of the Ohio River Valley for the new settlers that were flooding into the British colonies seeking farmland.
The most important French fort planned was intended to occupy a position at "the Forks", where the Allegheny and Monongahela rivers meet to form the Ohio River in present-day Pittsburgh, Pennsylvania. Peaceful British attempts to halt this fort construction were unsuccessful, and the French proceeded to build the fort they named Fort Duquesne. British colonial militia from Virginia accompanied by Chief Tanacharison and a small number of Mingo warriors were sent to drive them out. Led by George Washington, they ambushed a small French force at Jumonville Glen on 28 May 1754 killing ten, including commander Joseph Coulon de Jumonville. The French retaliated by attacking Washington's army at Fort Necessity on 3 July 1754 and forced Washington to surrender. These were the first engagements of what would become the worldwide Seven Years' War.
Britain and France did not negotiate a solution after receiving news about the clash. The two countries eventually sent regular troops to North America to enforce their claims. The first British action was the assault on Acadia on 16 June 1755 in the Battle of Fort Beauséjour, which was immediately followed by their expulsion of the Acadians. In July, British Major General Edward Braddock led about 2,000 regular army troops and provincial militia on an expedition to retake Fort Duquesne, but the expedition ended in disastrous defeat. In further action, Admiral Edward Boscawen fired on the French ship Alcide on 8 June 1755, capturing it and two troop ships. In September 1755, British colonial and French troops met in the inconclusive Battle of Lake George.
The British navy harassed French shipping beginning in August 1755, seizing hundreds of ships and capturing thousands of merchant seamen even though the two nations were nominally at peace. Incensed, France prepared to attack Hanover, whose prince-elector was also the King of Great Britain and Minorca. Britain concluded a treaty with Prussia in which the latter agreed to protect Hanover. In response France concluded an alliance with its long-time enemy Austria, an event known as the Diplomatic Revolution.
In Europe
In the War of the Austrian Succession, which lasted from 1740 to 1748, the Prussian King Frederick II had seized the prosperous province of Silesia from Austria. Empress Maria Theresa of Austria had signed the Treaty of Aix-la-Chapelle in 1748 in order to gain time to rebuild her military forces and to forge new alliances.
The War of the Austrian Succession had seen the belligerents aligned on a time-honoured basis. France's traditional enemies, Great Britain and Austria, had coalesced just as they had done against Louis XIV. Prussia, the leading anti-Austrian state in Germany, had been supported by France. Neither group, however, found much reason to be satisfied with its partnership: British subsidies to Austria produced nothing of much help to the British, while the British military effort had not saved Silesia for Austria. Prussia, having secured Silesia, came to terms with Austria in disregard of French interests. 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. The collapse of that system and the aligning of France with Austria and of Great Britain with Prussia constituted what is known as the "Diplomatic Revolution" of 1756.
In 1756 Austria was making military preparations for war with Prussia and pursuing an alliance with Russia for this purpose. On 2 June 1746, Austria and Russia had signed the 1746 Treaty of Saint Petersburg,
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. Alexey Bestuzhev-Ryumin, grand chancellor of Russia from 1744 to 1758 under Empress Elizabeth, was hostile both to France and to Prussia, but he could not persuade Austrian statesman Wenzel Anton von Kaunitz to commit to offensive designs against Prussia so long as Prussia was able to rely on French support.
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. If war against France for colonial expansion were to resume, then Hanover had to be secured against Franco-Prussian attack giving East Prussia to Poland. France was very much interested in colonial expansion and was willing to exploit the vulnerability of Hanover in war against Great Britain, but it had no desire to divert forces to Central Europe for Prussia's interest.
French policy was, moreover, complicated by the existence of the Secret du Roi—a system of private diplomacy conducted by King Louis XV. 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. Louis's goals for le Secret du roi included the Polish crown for his kinsman Louis François de Bourbon, Prince of Conti, and the maintenance of Poland, Sweden, and the Ottoman Empire as French allies in opposition to Russian and Austrian interests.
Frederick saw Saxony and Polish West Prussia as potential fields for expansion, but could not expect French support if he started an aggressive war for them. If he joined the French against the British in the hope of annexing Hanover, he might fall victim to an Austro-Russian attack. The hereditary elector of Saxony, Frederick Augustus II, was also elective King of Poland as Augustus III, but his two territories were physically separated by the Prussian possessions of Brandenburg and Silesia. Neither Saxony nor Poland could pose as a great power: Saxony was merely a buffer between Prussia and Austrian Bohemia, whereas Poland, despite its union with the ancient lands of the Grand Duchy of Lithuania, was prey to pro-French and pro-Russian factions. A Prussian scheme for compensating Frederick Augustus with Bohemia in exchange for Saxony presupposed further spoliation of Austria.
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. In 1751 Britain joined the Austro-Russian alliance,
but complications arose. Britain's basic framework for the alliance itself was to protect Hanover's interests against France. At the same time, Kaunitz kept approaching the French in the hope of establishing just such an alliance with Austria. Not only that, France had no intention to ally with Russia, who, years earlier, had meddled in France's affairs during Austria's succession war. France also saw the dismemberment of Prussia as threatening to the stability of Central Europe.
Years later, Kaunitz kept trying to establish France's alliance with Austria. He tried as hard as he could to avoid Austrian entanglement in Hanover's political affairs, and was even willing to trade the Austrian Netherlands for France's aid in recapturing Silesia. Frustrated by this behaviour and by the Dutch Republic's insistence on neutrality, Britain soon turned to Russia. On 30 September 1755, Britain pledged financial aid to Russia in order to station 50,000 troops on the Livonian-Lithuanian border, so they could defend Britain's interests in Hanover immediately. Bestuzhev, assuming the preparation was directed against Prussia, was more than happy to accede to the request of the British. Unbeknownst to the other powers, King George II also made overtures to the Prussian king, Frederick, who, fearing the Austro-Russian intentions, was also desirous of a rapprochement with Britain. On 16 January 1756, the Convention of Westminster was signed, whereby Britain and Prussia promised to aid one another; the parties expressed a wish to achieve lasting peace and stability in Europe.
The carefully coded words in the agreement proved no less catalytic for the other European powers. The results were absolute chaos. Empress Elizabeth of Russia expressed outrage at British duplicity. Not only that, but France was enraged and terrified by the sudden betrayal by its only ally, Prussia. Austria, particularly Kaunitz, used this situation to their utmost advantage. Now-isolated France was forced to accede to the Austro-Russian alliance or face ruin. Thereafter, on 1 May 1756, France and Austria signed the First Treaty of Versailles, in which both nations pledged 24,000 troops to defend each other in the case of an attack. This diplomatic revolution proved to be an important cause of the war; although both treaties were ostensibly defensive in nature, the actions of both coalitions made the war virtually inevitable.
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. Eighteenth-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, with lengthy sieges a common feature of armed conflict. Decisive field battles were relatively rare.
The Seven Years' War, like most European wars of the eighteenth century, was fought as a so-called cabinet war 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.
Coalitions
The leading members of the first coalition were Britain and Prussia. Aside from Prussia, seven minor German states within the Holy Roman Empire (HRE) allied with Great Britain and operated under British command and subsidies during the war. They consisted of Hanover (in personal union with the British crown since 1714), Hesse-Kassel, Brunswick-Wolfenbüttel, Saxe-Gotha-Altenburg, Würzburg, Ansbach, and Schaumburg-Lippe. Discounting Hanoverian troops who later entered the British army, these seven states contributed nearly 50,000 troops over the course of the war, a very high number for their small populations (almost half of these, 21,756 men, came from Hesse-Kassel). Portugal later joined the coalition after being invaded by Spain in 1762. Russia was briefly part of the coalition, placing 20,000 of its troops under Frederick's command in Silesia and threatening Austria's eastern flank by marching 45,000 troops into Mecklenburg following Peter III's ascension in January 1762, but exited the war after his death a few months later. Various minor Native American polities also fought alongside the British during the continental North American theatre, such as the Iroquois Confederacy.
The leading members of the second coalition were France and the Habsburg Monarchy (also known as the Austrian Monarchy), with Sweden joining in 1756 and Spain in 1762. Russia was initially the third major member of the coalition and fought heavily for most of the war but switched sides in early 1762 and withdrew by late 1762. The Habsburgs' territory (including Austria itself as well as Bohemia, the Austrian Netherlands, and part of Imperial Italy) was mostly within the Holy Roman Empire and other states of the HRE joined the Habsburgs, formally the HRE's sovereigns. The Habsburgs had successfully rallied the Imperial Diet to declare Reichskrieg against Prussia, freeing Frederick II's vassals from their obligations and allowing them to summon the Imperial Army to supplement the forces of their own hereditary lands. Notable HRE states that fought alongside the Habsburgs included Saxony, Bavaria, the Palatinate, Tuscany, Modena-Reggio, Mainz, Trier, Württemberg, Zweibrücken, and Anhalt-Zerbst. These states contributed forces to the Reichsarmee and Kaiserliche Armee and under the Kreis system. The Habsburgs viewed this as an important propaganda coup as it allowed them to present their war with Prussia as a lawful Imperial action preserving the peace of the Empire, rather than an Austrian war. The burden was not evenly distributed; Mainz for example provided 15,000 troops for both the Austrian army and the Kreistruppen over the course of the war, a considerable burden for a state of about a third of a million inhabitants. The de facto independent Bengal Subah also fought the British in India with French support. In North America, the Wabanaki Confederacy sided with the French.
Much of the HRE remained neutral in the conflict, with the largest neutral polity being Piedmont-Savoy.
Strategies
For much of the eighteenth century, France approached its wars in the same way. It would let colonies defend themselves or would offer only minimal help (sending them limited numbers of troops or inexperienced soldiers), anticipating that fights for the colonies would most likely be lost anyway. This strategy was to a degree forced upon France: geography, coupled with the superiority of the British navy, made it difficult for the French navy to provide significant supplies and support to overseas colonies. Similarly, several long land borders made an effective domestic army imperative for any French ruler. Given these military necessities, the French government, unsurprisingly, based its strategy overwhelmingly on the army in Europe: it would keep most of its army on the continent, hoping for victories closer to home. The plan was to fight to the end of hostilities and then, in treaty negotiations, to trade territorial acquisitions in Europe to regain lost overseas possessions (as had happened in, e.g., the Treaty of Saint-Germain-en-Laye and the Treaty of Aix-la-Chapelle). This approach did not serve France well in the war, as the colonies were indeed lost, and although much of the European war went well, by its end France had few counterbalancing European successes.
The British—by inclination as well as for practical reasons—had tended to avoid large-scale commitments of troops on the continent. They sought to offset the disadvantage of this in Europe by allying themselves with one or more continental powers whose interests were antithetical to those of their enemies, particularly France. By subsidising the armies of continental allies, Britain could turn London's enormous financial power to military advantage. In the Seven Years' War, the British chose as their principal partner the most brilliant general of the day, Frederick the Great of Prussia, then the rising power in central Europe, and paid Frederick substantial subsidies for his campaigns. This was accomplished in the Diplomatic Revolution of 1756, in which Britain ended its long-standing alliance with Austria in favour of Prussia, leaving Austria to side with France. In marked contrast to France, Britain strove to prosecute the war actively overseas, taking full advantage of its naval power. The British pursued a dual strategy—naval blockade and bombardment of enemy ports, and rapid movement of troops by sea. They harassed enemy shipping and attacked enemy colonies, frequently using colonists from nearby British colonies in the effort. Overall, the war cost Prussia 139 million thalers; of these 58.3 million (42%) came from Prussian taxes and savings, 27 million (19%) came from British subsidies, and the rest came from either currency debasement or pillage of other northern German states, especially Saxony.
The Russians and the Austrians were determined to reduce the power of Prussia, the new threat on their doorstep, and Austria was anxious to regain Silesia, lost to Prussia in the War of the Austrian Succession. Along with France, Russia and Austria agreed in 1756 to mutual defence and an attack by Austria and Russia on Prussia, subsidized by France.
Europe
William Pitt the Elder, who entered the cabinet in 1756, had a grand vision for the war that made it entirely different from previous wars with France. As prime minister, Pitt committed Britain to a grand strategy of seizing the entire French Empire, especially its possessions in North America and India. Britain's main weapon was the Royal Navy, which could control the seas and bring as many invasion troops as were needed. He also planned to use colonial forces from the thirteen American colonies, working under the command of British regulars, to invade New France. In order to tie the French army down he subsidized his European allies. Pitt was head of the government from 1756 to 1761, and even after that the British continued his strategy. It proved completely successful. Pitt had a clear appreciation of the enormous value of imperial possessions, and realized the vulnerability of the French Empire.
1756
The British prime minister, the Duke of Newcastle, was optimistic that the new series of alliances could prevent war from breaking out in Europe. However, a large French force was assembled at Toulon, and the French opened the campaign against the British with an attack on Minorca in the Mediterranean. A British attempt at relief was foiled at the Battle of Minorca, and the island was captured on 28 June (for which Admiral Byng was court-martialed and executed). Britain formally declared war on France on 17 May, nearly two years after fighting had broken out in the Ohio Country.
Frederick II of Prussia had received reports of the clashes in North America and had formed an alliance with Great Britain. On 29 August 1756, he led Prussian troops across the border of Saxony, one of the small German states in league with Austria. He intended this as a bold pre-emption of an anticipated Austro-French invasion of Silesia. He had three goals in his new war on Austria. First, he would seize Saxony and eliminate it as a threat to Prussia, then use the Saxon army and treasury to aid the Prussian war effort. His second goal was to advance into Bohemia, where he might set up winter quarters at Austria's expense. Thirdly, he wanted to invade Moravia from Silesia, seize the fortress at Olmütz, and advance on Vienna to force an end to the war.
Accordingly, leaving Field Marshal Count Kurt von Schwerin in Silesia with 25,000 soldiers to guard against incursions from Moravia and Hungary, and leaving Field Marshal Hans von Lehwaldt in East Prussia to guard against Russian invasion from the east, Frederick set off with his army for Saxony. The Prussian army marched in three columns. On the right was a column of about 15,000 men under the command of Prince Ferdinand of Brunswick. On the left was a column of 18,000 men under the command of the Duke of Brunswick-Bevern. In the centre was Frederick II himself, with Field Marshal James Keith commanding a corps of 30,000 troops. Ferdinand of Brunswick was to close in on the town of Chemnitz. The Duke of Brunswick-Bevern was to traverse Lusatia to close in on Bautzen. Meanwhile, Frederick and Keith would make for Dresden.
The Saxon and Austrian armies were unprepared, and their forces were scattered. Frederick occupied Dresden with little or no opposition from the Saxons. At the Battle of Lobositz on 1 October 1756, Frederick stumbled into one of the embarrassments of his career. 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. Frederick actually fled the field of battle, leaving Field Marshal Keith in command. Browne, however, also left the field, in a vain attempt to meet up with an isolated Saxon army holed up in the fortress at Pirna. As the Prussians technically remained in control of the field of battle, Frederick, in a masterful coverup, claimed Lobositz as a Prussian victory. The Prussians then occupied Saxony; after the siege of Pirna, the Saxon army surrendered in October 1756, and was forcibly incorporated into the Prussian army. The attack on neutral Saxony caused outrage across Europe and led to the strengthening of the anti-Prussian coalition. The Austrians had succeeded in partially occupying Silesia and, more importantly, denying Frederick winter quarters in Bohemia. Frederick had proven to be overly confident to the point of arrogance and his errors were very costly for Prussia's smaller army. This led him to remark that he did not fight the same Austrians as he had during the previous war.
Britain had been surprised by the sudden Prussian offensive but now began shipping supplies and £670,000 (equivalent to £124,000,000 in 2024) to its new ally. A combined force of allied German states was organised by the British to protect Hanover from French invasion, under the command of the Duke of Cumberland. The British attempted to persuade the Dutch Republic to join the alliance, but the request was rejected, as the Dutch wished to remain fully neutral. Despite the huge disparity in numbers, the year had been successful for the Prussian-led forces on the continent, in contrast to the British campaigns in North America.
1757
On 18 April 1757, Frederick II again took the initiative by marching into the Kingdom of Bohemia, hoping to inflict a decisive defeat on Austrian forces. After winning the bloody Battle of Prague on 6 May 1757, in which both forces suffered major casualties, the Prussians forced the Austrians back into the fortifications of Prague. The Prussian army then laid siege to the city. In response, Austrian commander Leopold von Daun collected a force of 30,000 men to come to the relief of Prague. Following the battle at Prague, Frederick took 5,000 troops from the siege at Prague and sent them to reinforce the 19,000-man army under the Duke of Brunswick-Bevern at Kolín in Bohemia. Daun arrived too late to participate in the battle of Prague, but picked up 16,000 men who had escaped from the battle. With this army he slowly moved to relieve Prague. The Prussian army was too weak to simultaneously besiege Prague and keep Daun away, and Frederick was forced to attack prepared positions. The resulting Battle of Kolín was a sharp defeat for Frederick, his first. His losses further forced him to lift the siege and withdraw from Bohemia altogether.
Later that summer, the Russians under Field Marshal Apraksin besieged Memel with 75,000 troops. Memel had one of the strongest fortresses in Prussia. However, after five days of artillery bombardment, the Russian army was able to storm it. The Russians then used Memel as a base to invade East Prussia and defeated a smaller Prussian force in the fiercely contested Battle of Gross-Jägersdorf on 30 August 1757. In the words of the American historian Daniel Marston, Gross-Jägersdorf left the Prussians with "a newfound respect for the fighting capabilities of the Russians that was reinforced in the later battles of Zorndorf and Kunersdorf". However, the Russians were not yet able to take Königsberg after using up their supplies of cannonballs at Memel, and Gross-Jägersdorf retreated soon afterwards.
Logistics was a recurring problem for the Russians throughout the war. The Russians lacked a quartermaster's department capable of keeping armies operating in Central Europe properly supplied over the primitive mud roads of eastern Europe. The tendency of Russian armies to break off operations after fighting a major battle, even when they were not defeated, was less about their casualties and more about their supply lines; after expending much of their munitions in a battle, Russian generals did not wish to risk another battle knowing resupply would be a long time coming. This long-standing weakness was evident in the Russian-Ottoman War of 1735–1739, where Russian battle victories led to only modest war gains due to problems supplying their armies. The Russian quartermasters department had not improved, so the same problems reoccurred in Prussia. Still, the Imperial Russian Army was a new threat to Prussia. Not only was Frederick forced to break off his invasion of Bohemia, he was also now forced to withdraw further into Prussian-controlled territory. His defeats on the battlefield brought still more opportunistic nations into the war. Sweden declared war on Prussia and invaded Pomerania with 17,000 men. Sweden felt this small army was all that was needed to occupy Pomerania and felt the Swedish army would not need to engage with the Prussians because the Prussians were occupied on so many other fronts.
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 convention removed Hanover from the war, leaving the western approach to Prussian territory extremely vulnerable. Frederick sent urgent requests to Britain for more substantial assistance, as he was now without any outside military support for his forces in Germany.
Things were looking grim for Prussia now, with the Austrians mobilising to attack Prussian-controlled soil and a combined French and Reichsarmee force under Prince Soubise approaching from the west. The Reichsarmee was a collection of armies from the smaller German states that had banded together to heed the appeal of the Holy Roman Emperor Franz I of Austria against Frederick. However, in November and December 1757, the whole situation in Germany was reversed. First, Frederick devastated Soubise's forces at the Battle of Rossbach on 5 November 1757 and then routed a vastly superior Austrian force at the Battle of Leuthen on 5 December 1757. Rossbach was the only battle between the French and the Prussians during the entire war. At Rossbach, the Prussians lost about 548 men killed while the Franco-Reichsarmee force under Soubise lost about 10,000 killed. Frederick always called Leuthen his greatest victory, an assessment shared by many at the time as the Austrian Army was considered to be a highly professional force. With these victories, Frederick once again established himself as Europe's premier general and his men as Europe's most accomplished soldiers. However, Frederick missed an opportunity to completely destroy the Austrian army at Leuthen; although depleted, it escaped back into Bohemia. He hoped the two smashing victories would bring Maria Theresa to the peace table, but she was determined not to negotiate until she had re-taken Silesia. Maria Theresa also improved the Austrians' command after Leuthen by replacing her incompetent brother-in-law, Charles of Lorraine, with Daun, who was now a field marshal.
Calculating that no further Russian advance was likely until 1758, Frederick moved the bulk of his eastern forces to Pomerania under the command of Marshal Lehwaldt, where they were to repel the Swedish invasion. In short order, the Prussian army drove the Swedes back, occupied most of Swedish Pomerania, and blockaded its capital Stralsund. George II of Great Britain, on the advice of his British ministers after the battle of Rossbach, revoked the Convention of Klosterzeven, and Hanover reentered the war. Over the winter the new commander of the Hanoverian forces, Duke Ferdinand of Brunswick (until immediately before a commander in the Prussian Army), regrouped his army and launched a series of offensives that drove the French back across the River Rhine. Ferdinand's forces kept Prussia's western flank secure for the rest of the war.
The British had suffered further defeats in North America, particularly at Fort William Henry. At home, however, stability had been established. Since 1756, successive governments led by Newcastle and Pitt had fallen. In August 1757, the two men agreed to a political partnership and formed a coalition government that gave new, firmer direction to the war effort. 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. This "dual strategy" would dominate British policy for the next five years.
Between 10 and 17 October 1757, a Hungarian general, Count András Hadik, serving in the Austrian army, executed what may be the most famous hussar action in history. When the Prussian king, Frederick, was marching south with his powerful armies, the Hungarian general unexpectedly swung his force of 5,000, mostly hussars, around the Prussians and occupied part of their capital, Berlin, for one night. The city was spared for a negotiated ransom of 200,000 thalers. When Frederick heard about this humiliating occupation, he immediately sent a larger force to free the city. Hadik, however, left the city with his hussars and safely reached the Austrian lines. Subsequently, Hadik was promoted to the rank of marshal in the Austrian Army.
1758
In early 1758, Frederick launched an invasion of Moravia and laid siege to Olmütz (now Olomouc, Czech Republic). Following an Austrian victory at the Battle of Domstadtl that wiped out a supply convoy destined for Olmütz, Frederick broke off the siege and withdrew from Moravia. It marked the end of his final attempt to launch a major invasion of Austrian territory. In January 1758, the Russians invaded East Prussia, where the province, almost denuded of troops, put up little opposition. East Prussia had been occupied by Russian forces over the winter and would remain under their control until 1762, although it was far less strategically valuable to Prussia than Brandenburg or Silesia. In any case, Frederick did not see the Russians as an immediate threat and instead entertained hopes of first fighting a decisive battle against Austria that would knock them out of the war.
In April 1758, the British concluded the Anglo-Prussian Convention with Frederick in which they committed to pay him an annual subsidy of £670,000. Britain also dispatched 9,000 troops to reinforce Ferdinand's Hanoverian army, the first British troop commitment on the continent and a reversal in the policy of Pitt. 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. Despite Ferdinand's victory over the French at the Battle of Krefeld and the brief occupation of Düsseldorf, he was compelled by the successful manoeuvering of larger French forces to withdraw across the Rhine.
By this point Frederick was increasingly concerned by the Russian advance from the east and marched to counter it. Just east of the Oder in Brandenburg-Neumark, at the Battle of Zorndorf (now Sarbinowo, Poland), a Prussian army of 35,000 men under Frederick on 25 August 1758, fought a Russian army of 43,000 commanded by Count William Fermor. Both sides suffered heavy casualties—the Prussians 12,800, the Russians 18,000—but the Russians withdrew after battle, and Frederick claimed victory. The American historian Daniel Marston described Zorndorf as a "draw" as both sides were too exhausted and had taken such losses that neither wished to fight another battle with the other. In the undecided Battle of Tornow on 25 September, a Swedish army repulsed six assaults by a Prussian army but did not push on Berlin following the Battle of Fehrbellin.
The war was continuing indecisively when on 14 October Marshal Daun's Austrians surprised the main Prussian army at the Battle of Hochkirch in Saxony. Frederick lost much of his artillery but retreated in good order, helped by dense woods. The Austrians had ultimately made little progress in the campaign in Saxony despite Hochkirch and had failed to achieve a decisive breakthrough. After a thwarted attempt to take Dresden, Daun's troops were forced to withdraw to Austrian territory for the winter, so that Saxony remained under Prussian occupation. At the same time, the Russians failed in an attempt to take Kolberg in Pomerania (now Kołobrzeg, Poland) from the Prussians.
In France, 1758 had been disappointing and in the wake of this, a new chief minister, the Duc de Choiseul, was appointed. Choiseul planned to end the war in 1759 by making strong attacks on Britain and Hanover.
1759–1760
Prussia suffered several defeats in 1759. At the Battle of Kay, or Paltzig, the Russian Count Saltykov with 40,000 Russians defeated 26,000 Prussians commanded by General Carl Heinrich von Wedel. Though the Hanoverians defeated an army of 60,000 French at Minden, Austrian general Daun forced the surrender of an entire Prussian corps of 13,000 in the Battle of Maxen. Frederick himself lost half his army in the Battle of Kunersdorf (now Kunowice, Poland), the worst defeat in his military career and one that drove him to the brink of abdication and thoughts of suicide. The disaster resulted partly from his misjudgment of the Russians, who had already demonstrated their strength at Zorndorf and at Gross-Jägersdorf (now Motornoye, Russia), and partly from good cooperation between the Russian and Austrian forces. However, disagreements with the Austrians over logistics and supplies resulted in the Russians withdrawing east yet again after Kunersdorf, ultimately enabling Frederick to re-group his shattered forces.
The French planned to invade the British Isles during 1759 by accumulating troops near the mouth of the Loire and concentrating their Brest and Toulon fleets. However, two sea defeats prevented this. In August, the Mediterranean fleet under Jean-François de La Clue-Sabran was scattered by a larger British fleet under Edward Boscawen at the Battle of Lagos. In the Battle of Quiberon Bay on 20 November, the British admiral Edward Hawke with 23 ships of the line caught the French Brest fleet with 21 ships of the line under Marshal de Conflans and sank, captured, or forced many of them aground, putting an end to the French plans.