Knights Hospitalers
Knights Hospitalers were members of the military and religious Order of the Hospital of St. John of Jerusalem, sometimes called the Knights of St. John and the Knights of Jerusalem. Early in the 11th century the increasing number of pilgrimages to the holy city of Jerusalem led some Italian merchants to obtain from the city's Muslim rulers the right to maintain a Latin-rite church there. In connection with this church a hospital for ill or infirm pilgrims was established. When the Crusaders took Jerusalem, the master of the hospital was Gerard de Martignes, who created a separate order, the Friars of the Hospital of St. John of Jerusalem. In 1113, Pope Paschal II recognized the order, and it soon became apparent that military protection was necessary. Gerard de Martignes's successor, Raymond du Puy, reconstituted the order as a military one.

The Pope granted the order a red banner with a white cross in 1130; sometime between 1120 and 1160 it was laid down that a white cross should be worn on the black mantle of St. Augustine Order, of which the Hospitalers were a branch. The cross was probably a plain Latin one until the mid-13th century. Thus the Hospitalers were the Knights of the White Cross, in contra-distinction to the Knights Templars, the Knights of the Red Cross.

The members were divided into three classes - the Knights of Justice, who had to be of noble birth and had to be knights already; the chaplains, who served the spiritual needs of the establishment; and the serving brothers, who merely carried out orders given them. Besides these, there were the honorary members called donats, who contributed estates and funds to the order. Between 1136 and 1142 the Order received as gifts a number of key fortresses and, by 1157 at the latest, was engaged in warfare, not just defending its possessions. In 1168 it was able to send 500 knights on the invasion of Egypt, which suggests that by mid-century it was fulfilling a military as well as hospitaller role. The Hospitalers obtained a great income through gifts, and the necessity of caring for their estates led to the formation of subsidiary establishments all over Europe, the preceptories.

The knights took part in the major crusading campaigns, notably the capture in 1154 of Ascalon. When Jerusalem fell in 1187 to the Muslims, the Hospitalers established themselves at Margat and then in 1189 at Acre. The subsequent period was marked by rivalry with the Knights Templars and by military failure. In 1248 the mantle was replaced by a black surcoat with the white cross on the breast, but in 1259 this was changed to a red surcoat. Meanwhile, the hospital work of the order went on. In 1291 the knights were driven from the Holy Land by the fall of Acre and established themselves in Cyprus. They continued to combat the Muslims but now by sea rather than by land; the Hospitalers became the principal agents of convoys for pilgrims. Cyprus, however, was not the ideal place for the establishment, and the grand master, William de Villaret, planned the conquest of Rhodes from the Saracens, a conquest achieved by his brother and successor, Fulk (or Foulques) de Villaret in a special crusade in 1308-10.

The order grew stronger on Rhodes. They had received some benefit from the dissolution of the Knights Templars, and the wealth of their grand priories all over Europe had greatly increased. To some extent, at least, the change was accompanied by a decline in moral standards. The Knights of Rhodes, as they came to be known, matained their reputation as fighting men. In 1344 the knights, with the Genoese, inretook Smyrna and held it for a short time. In 1365, in conjunction with the king of Cyprus, they captured Alexandria, which, however, they were unable to retain.

The island of Rhodes was an important strategic point, and the Turks on their advance after the capture of Constantinople determined to take it. A heroic episode in medieval military history was the successful defense of Rhodes by the grand master, Pierre (later Cardinal) d'Aubusson, against the forces sent by Sultan Muhammad II. But the knights could not summon the means to resist indefinitely, and in 1522 the grand master Philippe de L'Isle Adam was forced to capitulate. The knights wandered homeless until in 1530 Holy Roman Emperor Charles V conferred upon them the sovereignty of the island of Malta.