The emigrant princes, on the contrary, filled all courts with the words uttered in favour of their cause in the declaration of Pilnitz. They wrote a letter to Louis XVI., in which they protested against the oath of the king to the constitution, forced, as they declared, from his weakness and his captivity. The king of Prussia, on receiving the circular of the French cabinet, in which the acceptance of the constitution was notified, exclaimed, "I see the peace of Europe assured!" The courts of Vienna and Berlin feigned to believe that all was concluded in France by the mutual concessions of the king and the Assembly. They made up their minds to see the throne of Louis XVI. abased, provided that the Revolution would consent to allow itself to be controlled by the throne. Russia, Sweden, Spain, and Sardinia were not so easily appeased. Catherine II. and Gustavus III., the one from a proud feeling of her power, and the other from a generous devotion to the cause of kings, arranged together, to send 40,000 Russians and Swedes to the aid of the monarchy. This army, paid by a subsidy of 15,000,000f. of Spain, and commanded by Gustavus in person, was to land upon the coast of France, and march upon Paris, whilst the forces of the empire crossed the Rhine. These bold plans of the two northern courts were displeasing to Leopold and the king of Prussia. They reproached Catherine with not keeping her promises, and making peace with the Turks. Could the emperor march his troops on the Rhine whilst the battles of the Russians and Ottomans continued on the Danube and threatened the remoter provinces of his empire? Catherine and Gustavus nevertheless did not abate in their open protection to the emigration party. These two sovereigns accredited ministers plenipotentiary to the French princes at Coblentz. This was declaring the forfeiture of Louis XVI., and even the forfeiture of France. It was recognising that the government of the kingdom was no longer at Paris, but at Coblentz. Moreover, they contracted a treaty of alliance, offensive and defensive, between Sweden and Russia in the common interest of the re-establishment of the monarchy.