The Seven Years’ War began in August of 1756 with Frederick of Prussia’s invasion of Saxony, and Maria Theresa was determined to maintain Austrian possession of Silesia. At the outset of the war, Austria was allied with France and Russia, and Prussia found allies in Great Britain and Portugal.
The Battle of Lowositz was won by the Prussians in 1756, although both armies withdrew for the winter, and both eventually regrouped. After Lowositz, Maria Theresa replaced her commander, Maximilian von Browne, with Prince Charles Alexander von Lorthringen, who defeated the Prussian forces at the Battle of Kolin in 1757, where Frederick of Prussia lost one-third of his force.
Great Britain quickly won a total victory in North America, and had captured all of New France by 1758, and France continued to suffer grave defeats at the hands of Great Britain in Europe, eventually retreating as far back as the Rhine River.
Attempted peace negotiations in 1759 yielded no result, but the tables of the war turned when Peter III became Emperor of Russia in 1762. Peter III withdrew Russian support and freed additional Prussian troops to combat Austria, where a victory was quickly won.
Austria lost no territory as a result of the Seven Years’ War, but the 1763 peace negotiations stripped France of most of its North American colonies.