original and intact early 1880's antique american victorian era decorative cast bronze "cahin-link" pattern exterior residential doorknob backplate with original unadorned swinging keyhole cover intact. the design was patented by rodolphe w. e. cheistesen of new britain, connecticut, assignor to the russell & erwin manufacturing company. the unusual pattern is described as "two series of rounded wire-like elevations crossing each other" with square rosette blocks containing gothic style quarterfoils. the doorknob backplate has a naturally aged (or oxidized) surface patina, left untouched. measures approximately 6 x 2 inches.