Which Spanish military order was founded in 1158 to defend the town of Calatrava?

The Order of Calatrava was the Spanish military order founded in 1158 to defend Calatrava.

Calatrava was a strategically important fortress on the frontier between Christian and Muslim-ruled territories in the Iberian Peninsula. When the Templars declined to defend it after its capture by Castile, cistercian monks and military supporters organized a new order under the leadership of Raymond of Fitero. King Sancho III of Castile recognized the foundation in 1158.

The order followed Cistercian religious discipline while maintaining a military role. Its knights fought in the long Christian reconquest of Iberia and became closely connected with the Castilian crown. The order’s headquarters later moved from Calatrava to other strongholds as political and military conditions changed.

It is often confused with the older Order of Santiago and the Order of Alcántara. These were separate Iberian military orders, although they sometimes cooperated and later came under royal administration.