The Franco-Austrian Alliance was a diplomatic and military alliance between France and Austria that was first established in 1756 after the First Treaty of Versailles. It lasted for much of the remainder of the century until it was abandoned during the French Revolution.
The alliance had its heyday during the Seven Years' War, when France and Austria joined forces to fight their mutual enemy, Prussia. After the allies' defeat, the intimacy of the alliance weakened, and by the 1780s, the alliance had become something closer to a formality. Austria even briefly considered the idea of entering the American War of Independence on Britain's side against France. During the French Revolution, when France first declared itself a constitutional monarchy and then overthrew and executed its king, the alliance had collapsed entirely. Austria actively tried to restore the French monarchy by going to war with the new French Republic.
Background
Throughout the 17th century and for the first half of the 18th century, France and Austria had been enemies and repeatedly fought wars against each other. During the War of the Polish Succession (1733–1735), France and its allies managed to weaken the power of Austria severely and forced it to give up small amounts of territory. In the War of the Austrian Succession (1740–1748), France allied with Prussia to attack Austria, which ended in Austria being forced to cede its richest and most prized province, Silesia, to the Prussians.
The failure of Britain in both wars to prevent Austria's losses led to a re-evaluation of the Anglo-Austrian Alliance, which had existed since 1731. Austria began to consider gaining new allies to help it to recover Silesia, which was the priority of Maria Theresa, the ruler of Austria.
France and Habsburg Austria were two traditional geopolitical great rivals in Europe. Between 1494 and 1697, the French-Habsburg rivalry had played out in the Italian Wars, the Thirty Years' War and the Nine Years' War. The rise of the absolute monarchy in France was motivated partially by a desire to seek allies against the Habsburgs, even the interests of the state went against the Church (as was the case in the Franco-Ottoman alliance or the Heilbronn League, with Protestant princes against the Habsburg-led Catholic League during the Thirty Years' War). That made the alliance a major diplomatic realignment for both France and Austria.
Diplomatic Revolution
By 1754, six years after the Treaty of Aix-la-Chapelle had brought the previous war to an end, a new figure, Count von Kaunitz, had risen to power in Vienna as a close advisor of Maria Theresa. He was committed to ending the British alliance and to looking for a new military partner. His friendship with the French ambassador, Choiseul, provided a close link between Paris and Vienna. Choiseul indicated to Kaunitz that France was willing to consider a rapprochement with Austria despite the long history of conflict between the two states.
In 1756, Britain signed a limited defensive alliance with Prussia, Both Austria and French were outraged at what they perceived as a betrayal by their respective allies.
In response, Austria and France signed a defensive alliance of their own, the First Treaty of Versailles. It stipulated that if either was attacked by a third party, the other would come to its assistance. As Austria were now planning an attack on Prussia to retake Silesia, the treaty was seen as a way of preventing any other power from trying to intervene on the side of Prussia.
The sudden political changes formed part of what became known as the stately quadrille.
Seven Years' War
In August 1756, Frederick the Great of Prussia, fearing that his country was about to be overrun and partitioned by its enemies, launched a pre-emptive strike against Austria's ally, Saxony, which he succeeded in capturing. That triggered the declaration of the Seven Years' War, and Austria went to war with Prussia with France as an ally. The Treaty of St Petersburg saw Sweden and Russia join the anti-Prussian alliance. Britain was Prussia's only major ally but was at war with France only, not with Austria, Russia, Saxony or Sweden.