Henry marched on Italy, but in all European history there has been no drama more tremendous than the expiation of his sacrilege. To his soldiers the world was a vast space, peopled by those fantastic beings which are still seen on Gothic towers. These demons obeyed the monk of Rome, and his army, melting from about the emperor under a nameless horror, left him helpless. Gregory lay like a magician in the fortress of Canossa: but he had no need of carnal weapons, for when the emperor reached the Alps he was almost alone. Then his imagination also took fire, the panic seized him, and he sued for mercy. On August 7, 1106, Henry died at Liège, an outcast and a mendicant, and for five long years his body lay at the church door, an accursed thing which no man dared to bury. Gregory prevailed because, to the understanding of the eleventh century, the evidence at hand indicated that he embodied in a high degree the infinite energy. The eleventh century was intensely imaginative and the evidence which appealed to it was those phenomena of trance, hypnotism, and catalepsy which are as mysterious now as they were then, but whose effect was then to create an overpowering demand for miracle-working substances. The sale of these substances gradually drew the larger portion of the wealth of the community into the hands of the clergy, and with wealth went temporal power. No vested interest in any progressive community has probably ever been relatively stronger, for the Church found no difficulty, when embarrassed, in establishing and operating a thorough system for exterminating her critics. Under such a pressure modern civilization must have sunk into some form of caste had the mediæval mind resembled any antecedent mind, but the middle age, though superficially imaginative, was fundamentally materialistic, as the history of the crusades showed.