In Rome he restored, and in many places renewed, the walls of the city, which were for the greater part in ruins; adding to them certain towers, and enclosing within these some new fortifications that he built without the Castle of S. Angelo, with many apartments and decorations that he made within. The said Pontiff also had a project in his mind, of which he brought the greater part nearly to completion, of restoring or rebuilding, according as it might be necessary, the forty Churches of the Stations formerly instituted by the Saint, Pope Gregory I, who received the surname of Great. Thus he restored S. Maria Trastevere, S. Prassedia, S. Teodoro, S. Pietro in Vincula, and many other minor churches. But it was with much greater zeal, adornment, and diligence that he did this for six of the seven greater and principal churches--namely, S. Giovanni Laterano, S. Maria Maggiore, S. Stefano in Celio Monte, S. Apostolo, S. Paolo, and S. Lorenzo extra muros. I say nothing of S. Pietro, for of this he made an undertaking by itself.
The same Pope was minded to make the whole of the Vatican into a separate city, in the form of a fortress; and for this he was designing three roads that should lead to S. Pietro, situated, I believe, where the Borgo Vecchio and the Borgo Nuovo now are; and on both sides of these roads he meant to build loggie, with very commodious shops, keeping the nobler and richer trades separate from the humbler, and grouping each in a street by itself. He had already built the Great Round Tower, which is still called the Torrione di Niccola. Over these shops and loggie were to be erected magnificent and commodious houses, built in a very beautiful and very practical style of architecture, and designed in such a manner as to be sheltered and protected from all the pestiferous winds of Rome, and freed from all the inconveniences of water and garbage likely to generate unhealthy exhalations. All this the said Pontiff would have finished if he had been granted a little longer life, for he had a great and resolute spirit, and an understanding so profound, that he gave as much guidance and direction to the craftsmen as they gave to him. When this is so, and when the patron has knowledge of his own and capacity enough to take an immediate resolution, great enterprises can be easily brought to completion; whereas an irresolute and incapable man, wavering between yes and no in a sea of conflicting designs and opinions, very often lets time slip past unprofitably without doing anything. But of this design of Nicholas there is no need to say any more, since it was not carried into effect.