"Calatrava is the Arabic name of a castle recovered from the Moslems, in 1147, by the King of Castile, Alfonso VII, called ''el Emperador''. Located in what was then the southernmost border of Castile, this conquest was more difficult to keep than to make, especially at a time with neither standing armies nor garrisons were known. In part to correct this deficiency, the military orders such as Knights Templars were founded, where men could fulfill a vow of perpetual war against the Muslim. The Templars, however, were unable to hold Calatrava, and the king found further volunteer warriors when Raymond, Abbot of the Cistercian monastery of Fitero offered himself.
This step is said to have been suggested to the abbot by Father Diego Velázquez, a simple monk, but one who had been a knight, and thus was well acquainted with military matters. Diego was inspired with the idea of employing the lay brothers of the abbey to defend Calatrava. These Cistercian lay brothers--at that time a recent innovation in monastic life--not being in Holy orders, were variously employed in manual trades such as those of tending herds, construction, farm labor, or husbandry. Diego recommended that they become ''soldiers of the Cross''. Thus a new order was created in 1157.
Motivated by the desire for religious and pecuniary rewards, these brethren were eager to take the offensive against the Moors. When the Abbot Raymond died (1163), a certain Don García started to lead them in battle as their first grand master. At the same time, the choir monks, not without protest, left Calatrava to live under an abbot whom they had chosen, in the monastery of Cirvelos. Only Velasquez and a few other clerics, to act as chaplains, remained in Calatrava with the knights, Velasquez becoming prior of the whole community. This somewhat revolutionary arrangement was approved by the general chapter at Cîteaux, and by Pope Alexander III (1164).〔
A general chapter held at Cîteaux in 1187 gave to the Knights of Calatrava their definitive rule, which was approved in the same year by Pope Gregory VIII. This rule, modeled upon the Cistercian customs for lay brothers, was imposed upon the knights, besides the obligations of the three religious vows, the rules of silence in the refectory, dormitory, and oratory; of abstinence on four days a week, besides several fast days during the year; they were also obliged to recite a fixed number of paternosters for each day Hour of the Office; to sleep in their armour; to wear, as their full dress, the Cistercian white mantle with the scarlet cross fleur de lisée. Calatrava was subject not to Cîteaux, but to Morimond in Champagne, the mother-house of Fitero, from which Calatrava had sprung. Consequently, the Abbot of Morimond possessed the right of visiting the houses and of reforming the statutes of Calatrava, while the highest ecclesiastical dignity of the order, that of grand prior, could be held only by a monk of Morimond."