Military body of Portuguese knights, founded c.1146; the castle of Aviz was their headquarters. They adopted the Cistercian rule and became affiliated with the Spanish Knights of Calatrava. Under Infante Fernando they achieved deeds of valor in Africa. After 1551 the grand mastership of the order was, vested in the king, who used their wealth for his own purposes. The knights were dispensed from the vow of celibacy in 1492. They were suppressed in 1834.