Military Orders is a term applied to three celebrated fraternities which sprang up in the period of the Crusades (q.v.). They were religious associations which arose from a mixture of the religious enthusiasm and the chivalrous love of arms which almost equally formed the characteristics of mediaeval society. The first origin of such associations may be traced to the necessities of the Christian residents of the Holy Land, in which the monks, whose first duty had been to serve the pilgrims in the hospital at Jerusalem, were compelled, by the necessity of self-defense, to assume the character of soldiers as well as of monks. These were termed Knights of St. John. SEE HOSPITALLERS. The second, the order of the Templars (q.v.), and the third, the Teutonic Knights, were the outgrowth of the days of the Crusades. SEE KNIGHTHOOD. These military orders professed to unite religious vows with the duties and discipline of a warrior. The chief objects they claimed to have in view were to defend and support Christianity, by force of arms, against the Mohammedans; to keep the public roads of Palestine from being infested with robbers; and to assist the poor, and minister to the sick, among those who were prompted by the spirit of the times to visit, as pilgrims, the various places reputed to be scenes of our Lord's earthly career.
The inferior orders of Alcantara and Calatrava, in Spain, having for their immediate object the defence of their country against the Moors, as well as those of Avis, in Portugal, claimed to have been instituted for like reasons as those above mentioned. They followed the Cistercian rule, and all three differed from the Templars and the Knights of St. John in being permitted by their institute to marry once. The same privilege was enjoyed in the Savoyard order of Knights of St. Maurice and the Flemish order of St. Hubert. On the contrary, the Teutonic Knights, who had their origin in the Crusades, see TEUTONIC KNIGHTS, were bound by an absolute vow of chastity.
With the varying conditions of society, these religious associations have at various times been abolished or fallen into disuse; but most of them still subsist in the form of orders of knighthood, and, in some of them, attempts have recently been made to revive, with certain modifications, the monastic character which they originally possessed. See Lea, Hist. of Sacerdotal Celibacy, chapter 22; Giustinani, Ordini Militari, s.v.