a city of new Castile, in Spain, situated on the river Guadiana, 45 miles south of Toledo. W. Long. 4. 20. N. Lat. 39. 0.

Knights of Calatrava, a military order in Spain, instituted under Sancho III. king of Castile, upon the following occasion. When that prince took the strong fort of Calatrava from the moors of Andalusia, he gave it to the templars, who, wanting courage to defend it, returned it him again. Then Don Reymond, of the order of the Cistercians, accompanied with several persons of quality made an offer to defend the place, which the king thereupon delivered up to them, and instituted that order. It increased to much under the reign of Alphonso, that the knights desired they might have a grand master, which was granted. Ferdinand and Isabella afterwards, with the consent of pope Innocent VIII. reunited the grand-mastership of Calatrava to the Spanish crown; so that the kings of Spain are now become perpetual administrators thereof.

The knights of Calatrava bear a cross gules, flowered with green, &c. Their rule and habit was originally that of the Cistercians.