In the context of an expanding economy and the consolidation of guild participation in the government of the city, the second half of the thirteenth century saw a series of public works undertaken that would define the urban structure of Florence in the following centuries. These works responded to functional needs, but also indicated the emergence of an idea of the city as an aesthetic construct, capable of representing the condition and aspirations of a community through the arrangement of public spaces and a series of outstanding buildings.
The evolution of the municipal government system seen during the thirteenth century gave rise to the construction of a series of institutional seats, secular centres of a network of ideal and visual references to which the city’s religious complexes also belonged. In 1255, construction began on the Palazzo del Capitano del Popolo – today known as the Bargello – seat of the city’s highest military and judicial authority. Not far away, in 1299, work began on the Palazzo dei Priori, today’s Palazzo Vecchio, to house the legislative and executive bodies of the municipality. In 1296, construction also began on the great new cathedral, which was to be dedicated to Santa Maria del Fiore.
A new circuit of walls was planned, which had become necessary due to the growth of the villages outside the twelfth-century city walls. Designed around 1284 and built for the most part between 1299 and 1331 – finally arriving as far as the village of San Niccolò between the 1360sand 1380s – the new walls extended for about 8.5 km and encompassed an inner area five times larger than the previous one, making Florence one of the largest European cities of the time. The walls responded to the expectation of further expansion by encompassing a large strip of land surrounding the old city core; in the Oltrarno area, the expansion mainly affected the area of San Frediano and the Carmine, while in the hilly section, between the gates of San Giorgio and San Miniato, the mid thirteenth-century walls were reused.
The expansion of the circle transformed the city into an organism that was less densely packed, in which the peripheral areas alternated between open and built-up spaces, with rows of simple houses, large orchards and monastic settlements dotting the strip of land close to the walls. The city took on a more sprawling form also thanks to a decree issued after 1250, which required the many towers to be limited to a maximum height of 50 braccia (about 29 m).
A decisive contribution to the new emerging urban design was made by the churches of the mendicant orders. All built or rebuilt in grandiose form between the mid-thirteenth century and the first decades of the fourteenth, large squares were opened in front of them, rearranging and enriching the city’s system of public spaces. Among these interventions, the reorientation of the new church of Santa Maria Novella (1279) in the direction of the Arno and the development of the Umiliati complex in Borgo Ognissanti, which saw the creation of a square facing the river, are some of the signs of a new relationship with the main Florentine waterway, which was no longer considered as a mere infrastructure, but as a significant feature of the city’s image.
A new type of private palazzo also emerged, in keeping with the image of the entrepreneurial and mercantile elite. The shapeless aggregates of houses and towers that constituted the traditional homes of the consorteria (association of noble families) were replaced, as early as the last decades of the thirteenth century, by more compact residences made up of blocks of three or four floors, with uniform rows of windows and successions of arcades on the ground floor giving access to workshops and warehouses. The small private squares of the older settlements were replaced in some cases by inner courtyards, which tended to become increasingly spacious and regular.