Thus had the city of Florence, when the fifteenth century entered on its fourth decade, developed in both severe and graceful beauty, under the influence of an art which, notwithstanding foreign traditions, was, nevertheless, in its peculiarity and luxuriance, the growth of its own soil. In external appearance, likewise, Florence was the city of a rich, active, sovereign republic, which sought its honour rather in the grandeur and brilliancy of its public buildings, both for ecclesiastical and secular purposes, than in the luxury of private houses. The city was at once munificent and thrifty, and, through all change, however precipitate, held firmly by old tradition, as was expressed by the prevailing similarity of the character of the architecture, notwithstanding the development of successive styles. Most of the streets were and remained narrow, the number of large squares was inconsiderable, but these streets were well paved, when in Rome people waded for years longer in the deep mire and dust of streets provided only with a tile causeway on each side. The greater number of houses were built of massive stone. The number of projecting upper storeys which darkened the streets had lessened more and more in the course of years. Some restriction was put on this mode of building by the imposition of a tax, which in Giovanni Villani’s time brought in 7,000 florins. Subsequently, however, it was expressly forbidden by law, and under the first Duke many of the projecting storeys were pulled down, so that their number is now proportionally small. A greater evil was the projection of the roofs over the street, but this was not removed till 1766. Although no fortress was assigned to the chief magistrate of the city, he was provided with a secure residence, and one befitting the dignity of his position. The boundary wall of Florence was a remarkable work. It enclosed the foremost height on the left bank of the river, and was fortified with towers. The gates were magnificent, among which that of St. Nicolò, with its projecting double storey, offers an example of its kind as the only one in complete preservation since the transformation undertaken in the sixteenth century.