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. ALS in French, signed “R. of Orleans,” one page both sides, 4.5 x 7, black-bordered personal letterhead, May 7, 1879. In part: “I just arrived yesterday. I’ll be in Paris with my daughter and children. We’ll go to Chantilly…What day will you come and see us?” In fine condition. RRAuction COA.