18th/19th century (or earlier ?).
Bréau-sans-Nappe was one of the three lordships of Boinville, which was formerly part of the diocese of Chartres (now Boinville-le-Gaillard in Yvelines). Its castle, whose foundations date back to the Middle Ages, dates from the 15th century. Legend has it that King Henry IV had lunch in the park on a stone table, without a tablecloth.
Attractive object.
Dimensions: 50.31g 10 x 8.1 cm
The material on the back is missing two small washers.