Revolutionary Wars and the Battle of Valmy
Also called: French Revolutionary Wars, War of the First Coalition, La Marseillaise
Revolutionary France declared war on Austria, and at Valmy its army halted the Prussians advancing on Paris.

Horace Vernet · Public domain · Source
Vowing to defend and spread the Revolution, the Legislative Assembly declared war on Austria on 20 April 1792, and Prussia joined the Austrian side (the Revolutionary Wars; from 1793 the War of the First Coalition, joined by Britain, Spain and others). At first the French were driven back. In July the Assembly declared “the fatherland in danger”, and the song of the Marseille volunteers, La Marseillaise, spread. The Prussian commander, the Duke of Brunswick, threatened vengeance on Paris if the royal family were harmed.
Having taken Longwy and Verdun, the Prussians advancing on Paris met the revolutionary army of Dumouriez and Kellermann at Valmy in Champagne on 20 September 1792. After an artillery duel the Prussians withdrew. Casualties were only in the hundreds on each side, but it was the first time a revolutionary army had stopped one of Europe’s best. The next day the Convention abolished the monarchy. Goethe, who was present, is said to have written that a new epoch of world history began there.