The Cantabrian circle (Latin: circulus cantabricus) was a military tactic employed by ancient and to a lesser extent medieval horse archers. As Flavius Arrianus and Hadrian relate, this was the most habitual form to appear in combat of the Cantabri tribes, and Rome adopted it after the Cantabrian Wars. A group of horse archers or mounted javelin throwers would form a single-file rotating circle. As the archers came around to face the enemy formation they would let their missile fly. The effect was a continual stream of arrows or javelins onto an enemy formation.