The city within the wall

As the medieval period was drawing to its close, between the end of the fourteenth and the beginning of the fifteenth century, the form of the city had been more or less stabilized.
In part this depended on the fact that its development had stopped far short of what the extensive perimeter of the last circle of walls (1284-1333), basically the same as the present ring of boulevards dating to the nineteenth century, might have led one to expect. From that time on, up to the end of the nineteenth century, building activity depended less on an increase in population than on the operations of improvement, enlargement and renovation of structures considered outmoded or non-functional.

The aesthetic as well as functional criteria of regularity and order which appeared in Florence at the end of the thirteenth century were confirmed in the course of the fourteenth and are reflected in descriptions of the city in the 'chronicles' of Villani and others

The city that stood within the walls included:
the central area set on the Roman layout that was broken up or altered in early medieval times, densely built up with practically no green areas, characterized by the presence of operational centres for the city as a whole (religious, political, commercial);
the area between the lines of the walls built under Matilda (1078, Castello d'Altofronte, now Museo della Scienza, Via de' Castellani, Via dei Leoni, Via del Proconsolo, Piazza Duomo, Via de' Cerretani, Via Rondinelli, Via de' Tornabuoni, Borgo SS. Apostoli, Via Lambertesca) and the first walls built by the commune (1173-75; Castello dAltofronte, Via de' Vagellai, Via de' Benci, Via Verdi, Via S. Egidio, Via Bufalini, Via de' Pucci, Via Gori, Canto de' Nelli, Piazza Madonna, Via del Giglio, Via della Croce di Trebbio, Via del Moro as far as the Arno);
the area included between the last two circles (first and second communal walls), centered along the roads which led to the borghi or suburbs which had formed outside the first communal walls, and were organized in districts around the churches and convents that once stood outside the city. In this area residential building consisted of houses bordering the road, in general building lots with a frontage of 4-5 meters and developed in depth; vast green areas existed in proximity to the walls in the triangles formed by the main thoroughfares which branched out from the center to the gates.

Elements that were fundamental to the structuring of the walled city were the territorial thoroughfares which naturally corresponded to the principal gates and - as far as the north-south route is concerned to the four bridges over the Arno:
north-south route from Porta S. Gallo (extant in Piazza della Liberta) to Porta Romana (to be found in the square of the same name), by way of Via S. Gallo, Via de' Ginori, Borgo S Lorenzo, Via Roma, Via Por S. Maria, Ponte Vecchio Via Guicciardini, Via Romana; east-west route on this side of the Arno from the Porta alla Croce (extant in Piazza Beccaria) to Porta al Prato (extant) by way of Borgo la Croce, Borgo degli Albizi, Via del Corso, Via degli Strozzi, Via Palazzolo, the Prato;
east-west route on the other side of the Arno from Porta S. Niccolò (extant) to Porta S. Frediano (extant) by way of Via S. Niccolò, Via de' Bardi, Borgo S. Jacopo, Via S. Spirito, Borgo S. Frediano. Installations connected with trade between territory and city sprang up along these thoroughfares and in the squares touched upon (markets and retail businesses, hotels, hospitals (spedali), public baths, etc.).
The principal poles that centered around the churches of the religious orders which settled in the city in the thirteenth century (S. Maria Novella, S. Croce, SS. Annunziata - S. Marco, S. Spirito ecc.) were inserted in the vast areas in between and the internal network of streets was determined by the dwellings in the district. The structural configuration summarily described above can still be seen today: the successive perimeters of city walls and the routes leading from gate to gate are clearly visible in the grid of streets, of which they constitute fundamental elements, and the density of buildings in the various zones can also be discerned, apart from the nineteenth-century sectors of saturation and substitution (the square of the western sector of the central nucleus defined by Via Roma, Calimala, Porta Rossa, Tomabuoni, de' Pecori).

The focus of Medicean works of the period remains the church of San Lorenzo, traditionally considered family "property". Pope Leo X sponsored the competition for the church facade. Giulio dei Medici (later Pope Clement VII) built the new sacristy (1520-34), that was to serve as the family mausoleum, and then the Laurentian Library (1523-29) that was completed during the era of Cosimo I.
Starting from a study of Florentine architecture (Brunelleschi, Giuliano da Sangallo, Il Cronaca), Michelangelo his own personal vision. Rather than attempting to eliminate the contradictions of his era that made any solution presented as a fixed truth, recognizable by all, totally impossible, he translated the contradiction itself, the internal contrast, into an absolute value. The area Michelangelo designed in the New Sacristy and the Laurentian library is internal unto itself.
This does not mean that it complies with Brunelleschi's mode in the sense of space that summarizes and sublimates all relationships with the outside through the calculated harmony of the proportions, but rather to the extent that every other reality beyond that which is imposed in the Sacristy is precluded, excluded and eliminated. Therefore, the "facades" look towards the interior.
The space is the result of the practically obsessive repetition of the wall designed like an external "façade". It is a world created from the inside, and it is no coincidence that upon entering the Sacristy one loses all sense of orientation. The walls are not like those designed by Brunelleschi, two dimensional surfaces between the structural lines; they are plastic forms that pull downwards with their weight.
The positions and proportions of the architectural elements do not follow traditional rules, they were developed on the basis of dynamics that derive from this general concept. Therefore, they created continuously unstable equilibria, internal conflicts in tension (central portions that are narrower than the lateral creating an effect of distance, compressed niches and doors, dilated arches, etc.).
The same features return in the Laurentian Library where the dynamics of Michelangelo's vision, based on movement within tight boundaries and contrasts can be seen as they develop in sequence: the vestibule is decidedly vertical, the reading room expands in depth, the last, triangular room for rare books compressed and limited (not realized). The spatial qualifications of these sequences are perfectly consistent with the functional qualification.

Clement VII opposed Charles V. After the sack of Rome (1527 the Florentines rebelled. Once again they banished the Medici and reestablished a republican regime (with Niccolò Capponi as gonfalonier). The reconciliation between Clement VII and the Emperor brought with it an agreement that allowed the Medici to return to Florence.
The Republic was besieged for eleven months (1529-30) but in the end it was forced to yield. As a symbolic execution of the Republic the palace tower in Piazza della Signoria was destroyed. Governor General and Procurator of the city's fortifications in order to defend Florence against any attempt by Clement VII to take the city by force.
Michelangelo built the bastions in front of the gates of the Medieval circle of walls and fortified the entire hill of San Miniato with structures consisting of pressed earth mixed with straw and covered with raw bricks.

The siege of Florence led to massive destruction of the buildings closest to the walls and of the nearby villas and houses. Following this destruction-wreaked by the Florentines themselves to clear the field and caused by the siege-many of the areas buildings were markedly reconfigured the sixteenth and seventeenth centuries.

The complicated political events during the early decades of the sixteenth century had the effect of decreasing construction on the whole. However, one must point out the work done by Baccio d'Agnolo who created many residential buildings, in a simplified style with a plastered facade and often with a loggia below the roof.
Part of his success was due to the working system he organized and it would be important to shed light on this as regards the history of the relationships between the powers and the authorities involved in the construction of the buildings and the city.
Among the several buildings attributed to him in Via Ginori, Palazzo Taddei (1503-04 ca.) can be considered a prototype of residential housing for the most affluent classes during the first half of the sixteenth century. In the Palazzo Bartolini-Salimbeni (1517-20) that takes full advantage of its lovely position on Piazza Santa Trinita through a combination of rigor and imagination, one can clearly see that Baccio d'Agnolo was acquainted with Bramante's and Raphael's Roman projects. Baccio d'Agnolo also designed the belltower of Santo Spirito (1503-17) that was finished later, in 1566 to be exact, by order of Cosimo I.

Destruction was not the only effect of the terrible siege of 1529-30. The drop in population and overall political instability were not factors that favored intense building and construction.

The Fortress of San Giovanni, later known as the Fortezza da Basso to distinguish it from the San Giorgio or Belvedere fortress, was ordered by Alessandro (1534) in order to defend the city and to allow him to control any internal revolt that could be organized by the Medici's enemies and in that case, to provide a safe refuge for the ruling family and its supporters.

Reasons of law and order also seem to have been behind Alessandro de' Medici's orders to eliminate the projections or overhangs from the Medieval houses. An order to this effect was issued in 1533 for Via Larga.