Initially the army of the Duke of Brunswick met little resistance in its August advance on the French capital. In leisurely fashion he took the fortresses at Longwy and Verdun before proceeding through the Argonne forest. Opposing him was the Army of the Centre under General Francois Kellermann, joined by part of the Army of the North under General Charles Dumouriez. Together the Generals could deploy 36,000 men of dubious quality compared to the 34,000 professional troops under Brunswick.
At last, on September 20, the two armies met at a position prepared by the French at Valmy.
Both sides opened a cannonade until 1 pm, when the Prussian guns fell silent and their infantry, arrayed in two lines, marched forward in attack. Kellermann seized the moment: raising his hat on his sword he cried 'Vive la Nation!' and thousands of troops answered back in a great surge of patriotic enthusiasm. To the astonishment of the French, Brunswick halted his attack and withdrew - and he did not stop until he had gone back across the Rhine. Goethe, who was present with the allied army, rightly perceived the great historical significance of the French victory, for not only did it save Paris, it saved the Revolution itself. 'From here and today,' he told his colleagues, 'there begins a new epoch in the history of the world, and you can say that you were there.'
Gregory Fremont-Barnes, The French Revolutionary wars, Osprey publishing. p. 26
Poco después, como preludio a la ejecución de Luis XVI, la Convención nacional dictaría el edicto de la fraternidad bajo una sobredosis de neoconismo.
The National Convention declares, in the name of the French nation, that it will grant fraternity and assistance to all peoples who wish to recover their liberty, and instructs the Executive Power to give the necessary orders to the generals to grant assistance to these peoples and to defend those citizens who have been - or may be - persecuted for their attachment to the cause of liberty.
Acto seguido anexó Bélgica y le declaró la guerra a Gran Bretaña y Holanda. En Abril de 1792 la asamblea legislativa había declarado así la guerra a Austria
declares that the French nation, faithful to the principles consecrated in the constitution, not to undertake any war with a view to making conquest, and never to employ its forces against the liberty of any people, takes arms only to maintain its liberty and its independence. That the war which it is forced to sustain is not a war of nation against nation, but the just defense of a free people against the unjust aggression of a king.
That the French will never confound their brothers with their real enemies; that they will neglect nothing in order to alleviate the scourge of war, to spare and preserve property, and to cause to return upon those alone, who shall league themselves against its liberties, all the miseries inseparable from war.