The Roman Forum and the land between it and the Colosseum, though strictly within the limits of Monti, were in reality a neutral ground, the chosen place for all struggles of rivalry between the Regions. The final destruction of its monuments dates from the sacking of Rome by Robert Guiscard with his Normans and Saracens in the year one thousand and eighty-four, when the great Duke of Apulia came in arms to succour Hildebrand, Pope Gregory the Seventh, against the Emperor Henry the Fourth, smarting under the bitter humiliation of Canossa; and against his Antipope Clement, more than a hundred years after Otto had come back in anger to avenge Pope John. There is no more striking picture of the fearful contest between the Church and the Empire. [Illustration: PIAZZA DI SAN GIOVANNI IN LATERANO] Alexis, Emperor of the East, had sent Henry, Emperor of the Holy Roman Empire, one hundred and forty-four thousand pieces of gold, and one hundred pieces of woven scarlet, as an inducement to make war upon the Norman Duke, the Pope's friend. But the Romans feared Henry and sent ambassadors to him, and on the twenty-first of March, being the Thursday before Palm Sunday, the Lateran gate was opened for him to enter in triumph. The city was divided against itself, the nobles were for Hildebrand, the people were against him. The Emperor seized the Lateran palace and all the bridges. The Pope fled to the Castle of Sant' Angelo, an impregnable fortress in those times, ever ready and ever provisioned for a siege. Of the nobles Henry required fifty hostages as earnest of their neutrality. On the next day he threw his gold to the rabble and they elected his Antipope Gilbert, who called himself Clement the Third, and certain bishops from North Italy consecrated him in the Lateran on Palm Sunday.