Thus we have completed the second circuit of the old Imperial town as it was in the thirteenth and most of the first half of the fourteenth centuries. It was then a city of no mean size for the middle ages, but it was far from having attained its full development. New monasteries and churches and new suburbs sprang up outside the new line of fortification. As usually happens, the majority of the dwellers outside the walls were of the lower class: but, besides their houses, there were, especially towards the east, splendid gardens and properties belonging to the patrician families and also several large buildings, including the Katherine and Clara Convents, the Mary Hospital, and the Carthusian Monastery (now part of the German Museum). Buildings of this kind, close to and outside of the gates of the old town, would, if they fell into the hands of an enemy, be a continual menace to the peace and safety of the burghers. Hardly, therefore, was the second line of fortifications completed when it became necessary to protect the new suburbs with wall and ditch like the old town. It may be noted that even when the new enceinte, that is the _third_ or outer town wall, was finished, the second wall was still carefully preserved as a second line of defence. This was directly contrary to the advice of Macchiavelli "not to establish within the circuit of a city fortifications which may serve as a retreat to troops who have been driven back from the first line of entrenchments ... for there is no greater danger for a fortress than rear-fortifications whither troops can retire in case of a reverse; for once a soldier knows that he has a secure retreat after he has abandoned the first post, he does, in fact, abandon it and so causes the loss of the entire fortress." The Nurembergers, however, never favoured any policy that could even remotely suggest that of burning their boats. For a long time they kept their second line of defence. Thus in 1509 it came to the notice of the authorities that "the inner moat near the arsenals and granaries were filled up with dirt and rubbish, which at some future time might do harm to the town, and the neighbours were forbidden to empty any more rubbish into the moat, and the town architect was ordered to see to it that what had been thrown into it was either levelled or taken out and that the parapet was renewed." Similarly and in the same year the inhabitants of the neighbourhood of St. Katherinagraben (the present Peter Vischerstrasse) were refused leave to build a bridge over the existing moat.