During the late eleventh and early twelfth centuries military orders, which were based on the monastic orders, were formed. Composed mainly of lay brothers, these Orders combined fighting with religious life. The Orders were led by Knights and Sergeants.

According to Feudal Monarchy in the Latin Kingdom of Jerusalem during the Crusader era, "three great religio-military Orders, the Templars, Hospitallers, and Teutonic Knights were the military mainstay of the kingdom; they supplied knights, sergeants, and in some instances ships." The Orders were the greatest landholders, with the exception of the churches and monasteries. They acquired lands in a variety of ways, via gifts, conquest and purchase.

Both The Hospitallers and the Templars were military orders charged with the military defense of the Holy Land. However, despite the fact that they had much in common, they were in fact rivals. They were acknowledged as regular orders, held the same rank in Church and State, and were granted extensive privileges by the Vatican. They were exempt from tithes, had their own clergy, chapels and cemeteries.  The Teutonic Knights were relative latecomers to the Holy Land and as such – trouble carving a out a niche for themselves and gaining lands.

The Templars

The order of the Temple was comprised of knights who came to the Holy Land on a pilgrimage. Founded at about 1120, it was the first military order (unlike other orders it was strictly a military order, not a mixed one).

The knights were provided some land in King Baldwin's palace, on the Temple Mount in Jerusalem, near the al-Aqsa Mosque (which was mistakenly identified as the Temple of Solomon). Their title was, "pauvres chevaliers du temple" (Poor Knights of the Temple) and they soon became known as the knights of the Temple of Solomon. With time, the `Templar' nickname was used – there are suggestions that the nickname was already in use during the 1140s.

In the beginning the Templars were charged with safeguarding the pilgrims who came to the Holy Land, however, within a few years they took up arms in the name of Christendom's fight against the local Muslims.

Initially the Templars did not have a rule or a habit. However, Hugues de Payens traveled to the Council of Troyes to seek the consent of the church as well as new recruits. With help from St. Bernard, in 1129 the Knights Templars adopted the Rule of St. Benedict (which had recently been reformed by the Cistercians). In addition to perpetual vows they adopted the white habit and added a red cross to it.

The Templars were by all accounts successful. They built Chastel Pèlerin (Atlit), as well as the stronghold in Safad.

Hospitallers of St. John of Jerusalem

Hostelries (also known as hospices) were a necessity for pilgrims visiting the Holy Land, even before the days of the Crusades. With time they developed into infirmaries. Raymond of Provence was responsible for erecting a hospice that became an infirmary near the Church of the Holy Sepulchre. At the time, it was decreed that that the hospice would maintain a permanent staff of five physicians and three surgeons.

The Hospital of St. John, was founded in Jerusalem before the First Crusade (the exact date is cause of debate), for the care of the poor and sick. There are also differences of opinion, as to when the order first began assuming military responsibilities. It should be noted that not all the brothers had the same status. Some were infirmarians; others military brothers, while a third group served as chaplains. We know that some of the knights were professed knights who were bound to the order by a perpetual vow, while secular knights served only for a short time.

At the height of their power the Hospitallers had at least seven strongholds, 140 estates and about 19 thousand manors. Administering the revenue from these numerous holdings was no small job – the Grand Master of the Holy Land was charged with this job.

The Hospitallers who wore a black mantle with a white cross built the citadel at Acre as well as Belvoir.   

Teutonic Order

The German hospital established at Acre during the Third Crusade lead to the evolvement of the Teutonic Order. Their military organization was based on that of the Order of the Temple and they adopted the rule of St. John. In 1205, Innocent II gave them the right to wear a white habit with a black cross. The Teutonic Order faced stiff competition from the more established Templars and Hospitallers.