This Victorian passage door key escutcheon is either cast brass or cast bronze. The hardware manufactures of the late 1800s used both mediums. On some pieces it is hard to tell which is which. This fancy key-hole cover would have been placed under the door knob and rosette, usually on the backside of the door.
The piece measures 1 5/8 inches vertically and one inch horizontally. The key-hole opening is 3/4 inch long. Small screws or brads will be included for mounting.