Parents: William Duff Armstrong (1833-1899) Martha E Shults Armstrong (1843-1882)
Robert Armstrong's grandfather, John "Jack" Armstrong(1803-1857) is famous for his wrestling match with Abraham Lincoln. Mr. Lincoln and Jack Armstrong were lifelong friends thereafter.
Robert Armstrong's father William "Duff" Armstrong(1833-1899) was the defendant in the famous "Almanac Trial". Abraham Lincoln defended "Duff" and won his freedom for no fee due to his friendship with the Armstrong family.