At different times in its history, Occident has witnessed the development of Orders of Knighthood. In Rome, the Equestrian Knights, the Equites, were not really horsemen but priveleged citizens of lower rank than the Senatorial order. During the Xth century, in post-Carolingian Europe, from among the class of free men there appeared some who were experts in horseback combat.Templars, Hospitallers, Teutonic, many Spanish Orders of the Reconquista, the strange, to say the least, existence of these Catholic monks-warriors, eliminating their enemies in the name of God has taken on many aspects. Going far beyond the vain legends (treasure of the Templars etc.) here is a prestigious study of the whole of the Military Religious Orders. CONTENTS : Introduction - Milestones – At the origins…- The defense of the latin States – The trial of the Templars – in the Spain of the Reconquista – Implantation of the Orders, maps and legends – Around the Baltic – The Hospitallers at Rhodes – Organization and everyday life – What has become of the Military Orders ? – Glossary – A few Templar and Hospitaller sites in France.