The World Turned Upside Down

The Seven Years' War began with the most audacious diplomatic maneuver of the 18th century. In the spring of 1756, France and Austria — enemies for 250 years, since the age of Valois kings and Habsburg emperors — signed a formal alliance. Europe was thunderstruck. The Diplomatic Revolution, as historians call it, was not an accident.

It was the work of two determined women: Maria Theresa of Austria and the Marquise de Pompadour, Louis XV's chief mistress and political confidante.

Maria Theresa had a grievance that consumed her. In 1740, the 23-year-old empress had barely ascended her throne when Frederick II of Prussia — the young king everyone underestimated — invaded and seized Silesia, Austria's richest province. The War of Austrian Succession ended inconclusively in 1748; Silesia remained Prussian.

Maria Theresa spent the next eight years rebuilding her army, reforming her finances, and planning her revenge. But she could not take on Prussia alone. She needed France.

Pompadour provided the channel. France's ancient rivalry with Austria had always been about the balance of power in Europe — but Prussia was now the greater threat to that balance.

Through careful cultivation of the Austrian ambassador, Pompadour helped engineer what her enemies called the Renversement des alliances: France and Austria as partners. Russia, already hostile to Prussia, joined the coalition. Sweden and Saxony followed.

Against this coalition stood Prussia — small, outnumbered, and surrounded — and Britain, which needed Prussia to pin French armies in Europe while British forces seized French colonies worldwide.

Frederick the Great saw it coming. In August 1756, he received intelligence that Austria, France, and Russia were planning a coordinated invasion for the following spring. He made the decision that defined his reign: rather than wait to be attacked on three fronts simultaneously, he would strike first.

On August 29, 1756, Prussian armies crossed into Saxony without warning or declaration of war. The Seven Years' War had begun.