Anglo-Prussian alliance (1756)

The Anglo-Prussian Alliance was a military alliance created by the Westminster Convention between Great Britain and Prussia which lasted formally between 1756 and 1762 during the Seven Years' War. It allowed Britain to concentrate the majority of its efforts against the colonial possessions of the French-led coalition, while Prussia bore the brunt of the fighting in Europe. It ended in the final months of the conflict, and despite its end, strong ties between the two remained.

Creation
Since 1731 Britain had been tied to Prussia's major rival Austria by the Anglo-Austrian Alliance. Prussia had been allied to Britain's enemy France. Following the War of the Austrian Succession during which she has lost the valuable province of Silesia, the Austrian Empress Maria Theresa tried to gain British support for a proposed military action to reclaim it. When the British government refused she grew disenchanted with them - and in 1756 made an alliance with France. Suddenly without a major ally in continental Europe, the British hastily concluded a similar pact with Frederick the Great of Prussia hoping it would forestall a major European war by maintaining the European Balance of Power. Prussia had a number of leading British supporters including William Pitt.

In practice
Despite the British hope to avoid a war, Frederick launched a pre-emptive strike against Austria in August 1756 - overunning Saxony and Bohemia. However, he was soon faced with an onslaught of enemies including France, Austria, Sweden and Russia and was forced to retreat. By 1757 it appeared that without substantive British assistance - Prussia was about to collapse. Frederick had established a large and well-disciplined army - but it was continually short of money. The British began to send large financial subsidies to support their ally. On 11 April 1758 the two states concluded the Anglo-Prussian Convention formalising their alliance. Neither side would make peace without consulting the other.

Following the occupation of Emden, a British contingent was despatched to the continent to serve with the Duke of Brunswick, a Prussian ally - and they served to shield Frederick's western flank - allowing him to focus in other directions. Under Prussian pressure, the British-backed Hanoverian government repudiated the Convention of Klosterzeven and re-entered the war on Prussia's side. In spite of British aid the Prussian war effort still nearly collapsed in 1759 - despite an Allied victory at the Battle of Minden.

However from then until the end of the war, events turned largely in the favour of the Anglo-Prussian Allies. Britain had enjoyed an Annus Mirablis in 1759 defeating France in Europe, North America and Asia as well as repelling a planned French invasion. Britain won a number of key victories over Spain during 1762, and the Russian Empress died - leading them to withdraw from the war against Prussia.

Collapse
It was eventually dissolved in 1762 when Britain withdrew financial and military support for Prussian war aims in Continental Europe. Britain won more favourable terms at the Treaty of Paris, gaining a number of the colonial possessions they had captured from France and Spain. Prussia was able to retain Silesia, but did not achieve the acquisition of further large territories it had hoped for at the outbreak of war.

The two powers made distinctly separate peace agreements to end the war. In the years after the war, their relationship deteriorated - with Prussia rejecting approaches from Britain to form a similar alliance before and during the American War of Independence. Prussia instead concluded a fresh alliance with Russia in 1764 while Britain remained diplomatically isolated.

In the 1780s, after the American War, Britain and Prussia began to move closer again. They co-operated during the Dutch Crisis and the following year formed part of a Triple Alliance with the Dutch Republic. Following the outbreak of the French Revolution Britain and Prussia both took part in the various coalitions formed against France.