Union general (1831–1874) who commanded the Artillery Reserve of the Army of the Potomac at the Battle of Gettysburg. Original 2.5 x 4 carte-de-visite portrait by an anonymous studio, signed at the bottom of the image in black ink, “R. O. Tyler, Bvt. Maj. Genl. U. S. A.,” and signed and inscribed on the reverse, “To Mrs. Thomas, compliments of R. O. Tyler.” In very good condition, with scattered foxing and soiling, clipped upper corners, and a slight brush to the signature. RR Auction COA.