Louis XV of France - Seven Years' War

Seven Years' War

By 1755, a new European conflict was brewing, the Peace of Aix-la-Chapelle being but a sort of truce. Already, French and British were fighting each other in North America without a declaration of war. In 1755, the British seized 300 French merchant ships, in violation of international law. A few months later, on 16 January 1756, Great Britain and Prussia signed a treaty of "neutrality".

Frederick II had abandoned his French ally during the War of Austrian Succession, signing a separate peace treaty with Austria in December 1745. At the same time, French officials realized that the Habsburg empire of Austria was no more the danger it had been in the heyday of the Habsburgs, back in the 16th and 17th centuries, when they controlled Spain and most of Europe and presented a formidable challenge to France. The new dangerous power looming now on the horizon was Prussia. In a "reversal of alliances", the king signed the Treaty of Versailles with Austria on 1 April 1756, overruling his ministers and putting an end to more than 200 years of conflict with the Habsburgs. The new Franco-Austrian Alliance would last intermittently for the next thirty five years.

Louis apparently expected that joining with Austria would prevent another war on the continent by confronting Prussia with a counter-coalition. He was mistaken. Austria was bent on regaining Silesia, which Prussia had grabbed in 1740 and had not returned. At the end of August 1756, having learned that Austria was negotiating to enlist Russia against him, Frederick II invaded Saxony without a declaration of war. He soon defeated the unprepared Saxon and Austrian armies and occupied the whole of Saxony. The Saxon ruler's younger daughter was the Dauphin's wife and his elder daughter was married to Charles VII of Naples, a Bourbon cousin. Frederick's treatment of the Polish–Saxon royal family was seen as uncommonly disrespectful; moreover, Queen Maria Josepha, the dauphine's mother, died from a stroke some in France attributed to maltreatment, without evidence. Rumours of these actions by Frederick II shocked the French. The dauphine had a miscarriage as a result of the news coming from Saxony. Louis XV decided he was left with no choice but to enter the war.

Meanwhile, Britain declared war on France on 18 May 1756. The ensuing Seven Years' War (1756–1763) was to have profound consequences for France and Britain.

In 1757 French troops invaded Hanover, but were driven out by a counter-attack led by Ferdinand of Brunswick the following year.