The French invasion of Austria in 1813 was, alongside the 1815 invasion of England, one of the greatest tactical achievements of Napoleon I of France during the Imperial Wars. Following the perceived betrayal of Napoleon by Francis II of Austria and his Prussian allies during the attempted invasion of France put down at Grenoble and the failure of the Austro-Prussian seizure and conversion of central Germany, Napoleon's Grand Army launched an invasion of Austria from the East, catching Francis II's armies off-guard at Prislitz and then routing the Austrian forces at Budapest, with horrific casualties and mass surrenders. The campaign lasted less than three weeks, as Napoleon's forces entered Austria from the Ukraine on June 17 and captured Vienna on July 3.
The war resulted in Francis II being exiled to Egypt and Napoleon dividing the realms of Austria up amongst his most loyal German vassals, as well as annexing most of western Austria, including Vienna, into France's domains. The conscription of Austrian soldiers into the French army would help Napoleon in his bloody invasion of Italy the following year. It also resulted in the proxy government of Ferdinand the Austrian in Budapest for seven years, until his Duchy of Hungary was absorbed into the French Empire in 1820. The invasion of Austria is widely regarded as the precursor to the Austrian Purges between 1817-1819, when Austrian nobility was forced to swear loyalty to France or be executed as enemies of the state, which in turn resulted in a sizable exodus of upper class Austrians to the Americas, in particular Mexico, where the Hapsburg family eventually aligned with the local rulers to form a new American dynasty.