original 19th century american ornamental cast bronze "thistle" pattern exterior residential doorknob backplate and matching doorknob. the intricate organic design is attributed to chicago architect louis sullivan. the oversized escutcheon features deeply lobed leafage surrounded by delicate scrolls. the backplate and doorknob were fabricated by the chicago hardware company, chicago, il. exhibits an attractive surface patina. the large escutcheon contains a protruding collar or thimble and circular opening for a standard cylinder lock. the doorknob contains a chicago-niles patent shank. original cast brass swinging keyhole cover intact. measures 17 x 3 1/2 inches.