Lat. castellum ( diminutive form of castrum, fortress). The forts for the auxiliary troops covered an area of 1.5 to 6 ha and could station 500 to 1000 men. Since Claudian times the fort's were generally rectangular and reinforced with banks, ditches and walls or wooden palisades. The via principalis and the via praetoria, which continued towards the back as the via decumana, constitued the main right-angled axes of the fort. The most important buildings were also located on these roads.