The Declaration of Pillnitz was issued by the Austrian emperor Leopold, Marie Antoinette’s brother, after the royal family’s arrest at Varennes:
“His Majesty the Emperor [of Austria] and his Majesty the King of Prussia… jointly declare that they regard the present situation of his Majesty the king of France as a matter of common interest to all the sovereigns of Europe. They trust that this interest will not fail to be recognised by the powers whose aid is solicited; and that in consequence they will not refuse to employ… the most efficient means, in proportion to their resources, to place the king of France in a position to establish, with the most absolute freedom, the foundations of a monarchical form of government, which shall at once be in harmony with the rights of sovereigns and promote the welfare of the French nation.
In that case, their said Majesties the emperor and the king of Prussia are resolved to act promptly and in common accord with the forces necessary to obtain the desired common end. In the meantime, they will give such orders to their troops as are necessary in order that these may be ready to be called into active service.”
Leopold, Emperor of Austria
Frederick William, King of Prussia
August 27th 1791