Roman castellum Celemantia in Slovakia, at the Danube. Castellum is hard to define unequivocally. In sources it was described as a fortification, fort or fortress, which in practice also served as a watchtower.
Castellum is a word derived from a diminutive of castrum, or Roman camp – the so-called “little fort”. This is mentioned, among others, by Vegetius: “And if no ancient fortifications are to be met with, small forts must be built in proper situations, surrounded with large ditches, for the reception of detachments of horse and foot, so that the convoys will be effectually protected. For an enemy will hardly venture far into a country where he knows his adversary’s troops are so disposed as to be ready to encompass him on all sides”1.
