It is said that the order owed its constitution to Frederick, Duke of Swabia; but there is much obscurity, and little authentic record to determine this or to furnish particulars of the transaction.
The order seems, however, to have been confirmed by Pope Celestine III, the constitution and rules of the Templars and Hospitalers being taken as the model for the new order, Henry de Walpot being the first master. This appears to have happened about 1190, though some authorities maintain that it was not till 1191 or even later. While, therefore, the three great orders had much in common, there was this difference in their original foundation. The Hospitalers were at first a nursing order, and gradually became military; the Templars were always purely and solely military; while the Teutonic Knights were from the first both military and nursing.
Contemporary chroniclers compare the Teutonic Knights with the mystic living creature seen by Ezekiel, having the faces of a man and of a lion, the former indicating the charity with which they tended the sick; the latter, the courage and daring with which they met and fought the enemies of Christ.
The Teutonic Knights continued their care of the sick soldiers till Acre was taken in July, 1191, by the united forces of Philip Augustus, King of France, and Richard Coeur de Lion, King of England. After the capture of Acre by the Christian army, Henry de Walpot purchased a site within the city, and built a church and hospital for his order, the first that it possessed. To these buildings were gradually added lodgings for the members of the order, for pilgrims, and for the soldiers which were enlisted to assist the knights in the field.
All this cost a large sum of money; but, as many wealthy Germans had enrolled themselves as knights, means were not wanting as the occasion for them occurred and the requirements of the order developed. Among the greatest of the earlier benefactors was Frederick, Duke of Swabia, who contributed money and aided the progress of the order by his influence, and, when he died at Acre, was interred in the church of the knights. Contemporary writers speak in the highest terms of his virtues, saying that he lived a hero and died a saint.