Philip, who had now wearied of his elderly and unattractive wife, and also of being regarded as only the husband of the queen, was rejoiced at the summons of his father, Charles V., who desired him to return to Spain to receive the kingdom, that Charles might retire into convent life. By the abdication of Charles V., Philip II. became one of the most powerful monarchs in the world. He was king of united Spain; he was also king of Naples and Sicily, and duke of Milan; he was sovereign of the Low Countries; and as husband of the queen of England, who was devotedly attached to him, he had great influence in the affairs of that nation. The Cape Verde Islands and the Canaries were under his sway. A large portion of the Mediterranean coast in Africa was under his dominion; also the Philippine and Spice Islands, in Asia. He inherited those islands which Columbus had conferred upon Spain in the West Indies, and also the vast realms of Mexico and Peru. Such was the immense power now placed in the hands of this young prince not yet thirty years of age. Philip II. established his court at Madrid, and from his palace there sent forth his edicts over his wide domains. In 1558 Queen Mary of England died, being succeeded by her half-sister Elizabeth. Philip’s only regret for his wife was, no doubt, the loss of his hold upon the English crown. Before a year had elapsed he was married to the daughter of the king of France. This young princess, Elizabeth,—called in Spain, Isabella,—was only fourteen years of age, and had been previously betrothed to the son of Philip, Don Carlos, who was of the same age. The death of this young prince a few years afterwards, under very suspicious circumstances, caused many to think that he had been poisoned by the command of his father, who had imprisoned the prince at the time. Don Carlos and his father had frequent quarrels, and at last Carlos was said to have confessed to a priest that he desired to kill his father, and he asked absolution, which the priest refused to grant. The king was informed of all this. The young prince was thereupon imprisoned, with a strong guard to watch him, and he was reported to be mad. In the course of a few months Don Carlos died. Two stories regarding that event were told. Some historians consider Philip innocent of any attempt upon the life of his son, but others state that the physician of the prince was informed that it was very desirable that the death of Carlos should appear to result from natural causes; and that medicine was administered to the unsuspecting patient in such doses as slowly to accomplish the desired end. Philip II. was a fanatic in religion, and the terrible persecution of the Protestants during his reign has filled the world with horror, as the shocking stories have been told.