original early 20th century antique american interior passage door "mantua" pattern doorknob backplate or escutcheon designed and fabricated by the p. & f. corbin co., new britain, ct. the decorative backplate is comprised of stamped bronze metal with a mostly uniform patina. the original collar or thimble is tightly affixed to the backside of the doorknob escutcheon. measures approximately 9 x 2 1/2 inches.