Only in the early years of the most lurid century of the Middle Ages, when decentralization culminated, and the imagination began to gain its fullest intensity, did the period of monastic consolidation open with the foundation of Cluny. In 910 William of Aquitaine draw a charter [Footnote: Bruel, _Recueil des Chartes de l’Abbaye de Cluny_, I, 124.] which, so far as possible, provided for the complete independence of his new corporation. There was no episcopal visitation, and no interference with the election of the abbot. The monks were put directly under the protection of the pope, who was made their sole superior. John XI confirmed this charter by his bull of 932, and authorized the affiliation of all converts who wished to share in the reform. [Footnote: _Bull. Clun._ p. 2, col. 1. Also Luchaire, _Manuel des Institutions Françaises_, 93, 95, where the authorities are collected.] The growth of Cluny was marvellous; by the twelfth century two thousand houses obeyed its rule, and its wealth was so great, and its buildings so vast, that in 1245 Innocent IV, the Emperor Baldwin, and Saint Louis were all lodged together within its walls, and with them all the attendant trains of prelates and nobles with their servants. In the eleventh century no other force of equal energy existed. The monks were the most opulent, the ablest, and the best organized society in Europe, and their effect upon mankind was proportioned to their strength. They intuitively sought autocratic power, and during the centuries when nature favored them, they passed from triumph to triumph. They first seized upon the papacy and made it self-perpetuating; they then gave battle to the laity for the possession of the secular hierarchy, which had been under temporal control since the very foundation of the Church.