During the French Revolutionary Wars, the revolutionary armies boiled eastward, enveloping Switzerland in their battles against Austria. In 1798 Switzerland was completely overrun by the French and became the Helvetic Republic. The Helvetic Republic encountered severe economic and political problems. In 1798 the country became a battlefield of the Revolutionary Wars.

In 1803 Napoleon's Act of Mediation partially restored the sovereignty of the cantons, and the former tributary and allied territories of Aargau, Thurgau, Grisons, St.Gallen, Vaud and Ticino became cantons with equal rights.

The Congress of Vienna of 1815 fully re-established Swiss independence and the European powers agreed to permanently recognise Swiss neutrality. At this time, the territory of Switzerland was increased for the last time, by the new cantons of Valais, Neuchatel and Geneva.