What event led to the declaration of war on Austria on 20 April 1792?

The declaration of war on Austria on 20 April 1792 was indeed prompted by the Declaration of Pillnitz. This declaration was made by the monarchs of Austria and Prussia in August 1791, and it expressed their collective support for the King of France, Louis XVI, and their intent to intervene in France if necessary. The French revolutionary government interpreted this statement as a direct threat and justification for military action against Austria, as it indicated that foreign powers were prepared to use force to restore the French monarchy.

The declaration marked a significant escalation in tensions between revolutionary France and the monarchies of Europe, contributing to the broader conflict that characterized this period of the French Revolution. The French leaders believed that a pre-emptive strike against Austria would unite the French populace in support of the revolution and protect France from foreign intervention. Thus, the events surrounding the Declaration of Pillnitz and the revolutionary sentiment significantly influenced the decision to declare war.