CATHERINE II (1729-1796) Empress of Russia. L.S. as Grand Duchess, St. Petersburg December 10, 1758, to King Frederick II of Prussia; 1page folio (monogram stamp from the Henri Ledoux collection); in Russian. Letter of condolence on the death of Frederick II's brother, August-Guillaume of Prussia (1722-1758), general-in-chief of the Prussian army, who died on June 12, 1758.