Their military history is linked with that of the Iberian states. They assisted in the eviction of the Muslims and doing battle with them, sometimes separately, sometimes with the royal armies. They also had a share in the fatal dissensions which disturbed the Christians of Iberia and brought about more than one schism in the order. Finally they took part in the maritime expeditions against the Muslims. Thus arose the obligation imposed upon aspirants to serve six months in the galleys, which still existed in the eighteenth century, but from which exemption was easily purchased. Authority was exercised by a grand master assisted by a Council of Thirteen, which elected the grand master and had the right to depose him for due cause; they had supreme jurisdiction in all disputes between members of the order. The first grand master, Pedro Fernández de Castro, died in 1184. He had had 39 successors, among them several Spanish Infantes, when, in 1499, Ferdinand the Catholic induced the pope to assign to him the administration of the order. Under Charles V, Pope Adrian VI annexed to the crown of Spain the three great military orders (Alcántara, Calatrava, and Santiago) with hereditary transmission even in the female line (1522). Thenceforth the three orders were united under one government, though their titles and possessions remained separate. To discharge the detail of this administration, Charles V instituted a special ministry, the Council of Orders, composed of a president named by the king, whom he represented, and six knights, two delegates from each order. To this council belonged the presentation of knights to vacant commanderies and jurisdiction in all matters, civil or ecclesiastical, save the purely spiritual cases reserved for ecclesiastical dignitaries. Thus ended the autonomy of the orders, but not their prestige.