The War of the First Coalition (1792–1797) was the first major effort of multiple European monarchies to defeat Revolutionary France. France declared war on the Habsburg monarchy of Austria on 20 April 1792, and the Kingdom of Prussia joined the Austrian side a few weeks later.
These powers initiated a series of invasions of France by land and sea, with Prussia and Austria attacking from the Austrian Netherlands and the Rhine, and Great Britain supporting revolts in provincial France and laying siege to Toulon. France suffered reverses (Battle of Neerwinden, 18 March 1793) and internal strife (Revolt in the Vendée), and responded with extreme measures: the Committee of Public Safety formed (6 April 1793) and the levée en masse drafted all potential soldiers aged 18 to 25 (August 1793). The new French armies counter-attacked, repelled the invaders, and moved beyond France. French arms established the Batavian Republic as a satellite state (May 1795) and gained the Prussian Rhineland by the first Treaty of Basel. With the Treaty of Campo Formio, the Holy Roman Empire ceded the Austrian Netherlands to France and Northern Italy was turned into several French "Sister Republics". Spain made a separate peace accord with France (second Treaty of Basel) and the French Directory carried out plans to conquer more of the Holy Roman Empire of the German Nation (Germany and in 1795 northern Italy).
North of the Alps, Archduke Charles of Austria redressed the situation in 1796, but Napoleon carried all before him against Sardinia and Austria in northern Italy (1796–1797) near the Po Valley, culminating in the peace of Leoben and the Treaty of Campo Formio (October 1797). The First Coalition collapsed, leaving only Britain in the field fighting against France.