Let us consider, therefore, as the most conspicuous feature of Plantagenet London, her great religious Houses. We have seen what they were in Norman London. Already there were there in existence the Cathedral of St. Paul's, with its canons and priests, its army of singing men, clerks, boys, and servants--itself a vast monastic House; the Priory of St. Bartholomew; the House of St. Mary Overies; the Hospital of St. Katherine; the Priory of the Holy Trinity. After three hundred years, when we look again upon the map of London, and mark in color the sites of Monastery, Nunnery, Church, College, and Church-yard, it seems as if a good fourth part of the City area was swallowed up in ecclesiastical Houses. Not so much was actually covered by buildings of the Church, but at least a fourth of the City, counting the gardens and the courts and chapels, belonged to the Church and the religious Houses. Without such a map it is impossible to estimate the enormous wealth of the mediæval Church, its power, and its authority. It is impossible to understand without such a map how enormous was that Revolution which could shake off and shatter into fragments a power so tremendous. Because, as was London, so was every other city. If London had a hundred and twenty churches, Norwich had sixty; York had forty-five. If the country all round London was parcelled out among the religious Houses, so all over the land, manors here, and estates there, broad acres everywhere belonged to the monks. But though their property was enormous, their power was far beyond that conferred by any amount of property, for they held the keys of heaven and kept open the gates of hell.