Roman army marched in a column (agmen). The column was opened by the advance guard (agmen primum), made up of auxiliary units, followed by the main units (exercitus). The column was closed by the rear guard (agmen novissimum). Then the carts were driven. The camp servants also travelled on carts.
The military march could be fast (iter magnum) and regular (iter iustum), about 30 km per day. When the army was in enemy territory, horse and foot patrols (speculatores or expolatores) were dispatched to the legions. In the case of a terrain obstacle in the form of a river, patrols were launched ahead that investigated the depth and current of the river. Then they helped the infantry to get to the other side. The infantry was overcoming this obstacle by swimming or on light boats. When the too-strong current of the river did not allow for safe crossing of the river, people helped each other by building bridges.
During long marches through the ravaged areas, the troops erected granaries (horrea) at the crossroads for grain and stores for fodder for horses and other animals (foenilia or palearia) and shed with building wood, used to build war machines. The granaries were surrounded by palisades and watchtowers guarded by soldiers.
