formulated the principle, more useful to his remote successors than himself, of the Two Powers, Church and State, both derived from God and both entitled to absolute power in their respective spheres. On this principle the State should not interfere with episcopal elections, or with matters of faith and discipline; it should not exercise jurisdiction over the priesthood who are servants of the Church, or over Church estates since they are held in trust for God and the poor. This view was proclaimed to the world by Leo III, who caused to be set up in the Lateran a mosaic representing in an allegory his relations to the Empire. St. Peter sits enthroned above; Charles and Leo kneel to right and left, in the act of receiving from the Apostle the pallium and the gonfalon, the symbols of their respective offices. No powerful Emperor ever accepted the Gelasian principle entire. To refute it was, however, difficult, so well did it harmonise with the current conception of the State. Under the later Carolingians it became the programme both of reformers and of mere ecclesiastical politicians. The new monasteries, founded or reorganised under the influence of Cluny, placed themselves beneath the special protection of the Pope, thus escaping from secular burdens. The national hierarchies hailed the forgeries of the Pseudo-Isidore as the charter of ecclesiastical liberty. Pope Nicholas I took his stand at the head of the new movement, and gave it a remarkable development when he asserted his jurisdiction over the adulterous Lothaire II (863). Nicholas died before he couldgive further illustrations of his claim to be supreme, even over kings, in matters of morality and faith. From his time to that of Hildebrand there was no Pope vigorous enough to make a similar example. Dragged down by their temporal possessions to the level of municipal seigneurs and party instruments, the Popes from 867 to 962 were, at the best, no more than vigorous Italian princes. To that level they returned after the period of the Saxon Ottos (962-1002). In those forty years there were glimpses of a better future; the German Pope, Gregory V, allied himself to Cluny (996-999); as Sylvester II (999-1003) the versatile Gerbert of Aurillac--at once mathematician, rhetorician, philosopher, and statesman--entered into the romantic dreams of his friend and pupil, Otto III, and formed others on his own behalf which centred round the Papacy rather than the Empire. Sylvester saw in imagination the Holy See at the head of a federation of Christian monarchies. But fate was no kinder to him than to Otto; he outlived his boy patron only by a year. VI THE HILDEBRANDINE CHURCH