: sudes) was a stake carried by Roman legionaries for employment as a field fortification, sometimes also called vallus.
Each stake was made of hardwood, usually oak, about 150–180 cm (5–6 ft) long and about 50–100 mm (2–4 in) wide at the thickest point.
Experiments with reconstructions have been disappointing in that such barriers are not strong, as the symmetry of the stakes makes them easy to pull out of the ground.
It has been proposed that the stakes were lashed in pairs at intervals along a log or beam to form a Cheval de frise.
In the Battle of Mount Algidus (458 BC), Cincinnatus ordered his men to provide twelve valli each, and used them to build a fortification around the Aequi, who were, at the time, surrounding another Roman army.