The opportunity of this class might seem to have come when the Hohenstaufen Frederick II., grandson of Barbarossa, ascended the throne, and still more when, on attaining full age, he claimed the whole of the Peninsula as his family inheritance. Other Emperors had withstood the Papal claims, but none had ever proved an antagonist like Frederick. His quarrel seemed indeed to be with the Church itself, with its doctrines and morals as well as with the ambition of churchmen; and he offered the strange spectacle of a Roman Emperor--one of the twin lights in the Christian firmament--whose favour was less easily won by Christian piety, however eminent, than by the learning of the Arab or the Jew. When compelled at last to fulfil a promise extorted from him of conducting a crusade to the Holy Land, he scandalised Christendom by making friends of the Sultan, and by using his presence in the East, not for the deliverance of the Sepulchre, but for the furtherance of learning and commerce. Thrice excommunicated, he had his revenge by proving with how little concern the heaviest anathemas of the Church could be met by one who was armed in unbelief. Literature, art, and manners were sedulously cultivated in his Sicilian court, and among the able ministers whom he selected or formed, the modern idea of the State may be said to have had its birth. Free thinker and free liver, poet, warrior, and statesman, he stood forward against the sombre background of the Middle Ages a figure in every respect so brilliant and original as well to earn from his contemporaries the title of the Wonder of the World.