The Antesignani were excellent soldiers facing heavy infantry. There is a lot of controversy related to this unit. Vegetius defines this formation as “light infantry”, not reflecting its importance as a combat unit (Vegetius, De re militari, p. 34.).
In the “Civil War” of Caesar we meet the most sensible description of a unit that they were selected light infantrymen of assault troops. Marian Plezia, on the other hand, in his book “Słowniku łacińsko-polskim” probably most aptly calls this formation “commandos“.
These soldiers were armed with a spear, a few spears, a sword, lighter armour (a simple bronze breastplate instead of lorica hamata), a coolus helmet and a small oval shield (instead of a heavy scutum). During the march, the task of antesignani was to protect the marching columns and secure the area. In combat, these units protected/supported the legion attacked enemy skirmishers or accompanied in cavalry combat.