The "box lock" type of pistol shows up around 1750 when gunmakers tried moving the hammer from the side to the center in an effort to make pocket pistols easier to get out of said pocket. The squared chamber style came in around 1770, though I'm certain your Belgium made pair post dates that. Larger versions were also made, usually with screw off barrels and sometimes with spring bayonets attached below the barrel. Boom!;Stick!;cha-cha-cha! :thumbsup: