The Heerbann (also formerly Heermannie, Mid. Latin: Heribannus, French: Arrière-ban), in the Imperial Military Constitution (Reichsheeresverfassung) of the Holy Roman Empire, was the call to all free landowners capable of bearing arms to participate in a military campaign, i.e. in an imperial war (Reichskreig). However, as the feudal system in the Holy Roman Empire developed in the Early Middle Ages, the Heerbann became superfluous as a means of raising armies and increasingly fell into disuse after the death of Charlemagne.