In 1856, Morny was sent as special envoy to the coronation of Alexander II of Russia and brought home a wife, Princess Sophie Troubetzkoi, who through her connections greatly strengthened his social position. Sophie was legally daughter of Prince Sergey Vasilyevich Trubetskoy, but may have been the illegitimate daughter of Nicholas I of Russia. In 1862, Morny was created a Duke. It is said that he aspired to the throne of Mexico, and that the French expedition sent to place Archduke Maximilian on the throne was prompted by Napoleon III's desire to thwart this ambition.