“The luster of their virtues and the glory they acquired daily by their valor raised a generous emulation among the nobility and gentry of Spain. We observed, at the beginning of this history, that the Moors, in the eighth century, took the greatest part of that kingdom from the Goths. ‘Tis well known, that the Christians which remained of that nation, flying from the persecution of the infidels, retired at first into the mountains of the Asturias, from whence they sallied out afterward, under the conduct of Pelagius, to defend their liberty and their religion. That prince, by little and little, enlarged the bounds of his kingdom. His successors were yet more prosperous; they recovered several provinces from the Moors; and these Christian princes, who carried on the war in different quart among others, to preserve a reciprocal independency among themselves, erected these provinces over which they assumed sovereignty into so many kingdoms. Such is the original of the kingdoms of Leon, Castile, Navarre, Aragon, Portugal, Valentia, &.”
“The Moors too, on their side, had cantoned out their conquest, and we find among those Barbarians the kings of Toledo, Cordova, Murcia, and Granada. The one was every day in action the other, and for several ages, there was continual war between them. Some Spanish gentlemen, in imitation of the Templars and Hospitallers, and for the defense of religion, formed hereupon several societies and military orders, composed only of the nobility and gentry of that nation: of the order of Calatrava is reckoned the most ancient. Don Sanchez, the third king Castile, having won from the Moors the city of Calatrava, a strong place and frontier of the kingdoms of Castile and Toledo, committed the government and defense of it to the Templars but these knights having afterward advice, that the kings of the Moors had joined their forces to besiege it, and finding themselves to few to defend it, they delivered the place back again to the king.”
“Sanchez had need of all his forces to keep the field and make head against the Moors, who threatened, at the same time, to break into Castile. That prince, in this distress, declared, that if anyone was able and brake enough to undertake the defense of Calatrava, he would give it to him in property, to be held under the immediate sovereignty of his crown. But the formidable power of the Moors had so intimidated the most of the grandees of his court, that there was not who offered to throw himself into a place which was going to have at the foot of its wall the whole forces of the infidels.”
Source: The History of the Knights Hospitallers of St. John of Jerusalem …, Volume 1 By Vertot (abbé de)