late 19th century american ornamental cast bronze "thistle" pattern exterior residential doorknob backplate. the intricate organic is design attributed to chicago architect louis sullivan. the oversized escutcheon features deeply lobed leafage surrounded by delicate scrolls. the backplate was fabricated by the chicago hardware company, chicago, il. exhibits an attractive surface patina aged nicely over time. contains a protruding collar or thimble and circular opening for a standard cylinder lock. measures approximately 16 1/2 x 3 1/2 inches.