These wheellock hand mortars, or katzenkopf, are an example of a weapon made and used for everything from front line military application to civilian parades to simple decoration. The pair we are looking at today are of the middle sort – they are signaling arms or firework launchers in the German or Dutch style from the early 1600s.
Martial grenade throwing mortars like this from the 17th century were typically built with more capacity for controlling recoil and aiming, but they were legitimate weapons made and used in battle. However more were made for throwing signal firecrackers and fireworks exhibitions – fireworks were a popular novelty among the royalty and aristocracy of the period. With a two-inch bore, you could launch quite the explosive from one of these!