sagittarii

thumb | right | alt=depiction of the use of arrows in combat | Sagittarii combat Sagittarii (Latin, plural form of sagittarius) is the Latin term for archers. The term sagittariorum in the title of an infantry or cavalry unit indicated a specialized archer regiment. Regular auxiliary units of foot and horse archers appeared in the Roman army during the early empire. During the Principate roughly two thirds of all archers were on foot and one third were horse archers. Mercenary foot archers already served with the Roman republican army, but horse archers were only introduced after the Romans came into conflict with Eastern armies that relied heavily on mounted archery in the 1st century BC, most notably the Parthians, whose mounted archers were decisive for Crassus's major defeat in the Battle of Carrhae. Since the time of Augustus however, Romans and Italians were also levied as dedicated archers. In the early 1st century BC horse archers were already in widespread use and even supported Roman campaigns against the Germanic tribes in Central Europe.

The normal weapon of Roman archers, both infantry and cavalry units, was the composite bow, although Vegetius recommended training recruits "arcubus ligneis" (with wooden bows), which may have been made in the northern European self bow tradition. It has been suggested that most Roman composite bows may have been asymmetric, with lower limbs shorter than the upper.