Grandson of King Louis-Philippe of France. He fought for the Union in the American Civil War, and then for France in the 1870 Franco-Prussian War. Original 2.25 x 4 carte-de-visite photo by Brady of Washington, signed below the image in black ink, “Robert d’Orleans, Capt & A.D.C.” In fine condition, with a slightly trimmed top edge. Accompanied by an unsigned post-war carte-de-visite photo by L. Angerer of Vienna. RR Auction COA.