The city of Florence used to be surrounded by high defensive walls. In Dan Brown’s Inferno, the adventures of the main character Robert Langon take place in this city.
The city walls surrounding Florence have been widened and rebuilt over the centuries six different times (although the actual count is controversial) to defend the city, which has undergone various expansions and contractions. Fortunately, solid and impressive remnants of the ancient city walls still survive: the doors (porte) and a few towers.
The First Circle
Even though the total number of circles remains a controversial topic (some sources speak of 4, others of 6), it is certain that the fortification began in Roman times and continued almost without interruption until 1333, the year of completion of the so-called circle of Arnolfo di Cambio.
The ancient Roman city was founded around 60 B.C.; it was located in the area between today’s Piazza del Duomo and Piazza Santa Trinita. It has its fulcrum in today’s Piazza della Repubblica, at the crossroads formed by the two main streets, cardo (Via Roma and Via Calimala) and decumanus (Via Strozzi and Via del Corso).
In the 2nd Century A.D., Florence had a population of about 10,000 inhabitants and was surrounded by a first wall.
Excavations have uncovered the remains of the first circle on the pavement of Via del Proconsolo, at Badia Fiorentina. This is evidenced by the original Roman circle called Via Por Santa Maria, one of the four existing ports at the time.
The Second Circle
After the fall of the Western Roman Empire, the city of Florence suffered a deep crisis, so much so that in the 6th Century it counted a mere 1,000 inhabitants.
Following the barbarian invasions and the Gothic war, a second wall, known as the Byzantine circle, was built by the Greeks in 550, protecting an area smaller than the Roman one.
According to some, this city would retain the beautiful Torre della Pagliazza in Piazza Elisabetta.
The Third Circle
Florence flourished once again (the population reached a population of 2,500), and by the beginning of 10th century, the city was enclosed by a wider third wall, which, for the first time, extended to the Arno river.
It became known as the Carolingian circle from the time of Carlo Magno.
The Eastern, Byzantine, and Western Roman line of the city walls were restored, and the walls were rebuilt on the south to include the villages that had sprouted near the river.
This new line ran along the Arno, on today’s Borgo SS. Apostoli, Via Lambertesca, the disappeared Castello d’Altafonte, Via de’ Castellani, and Via de’ Leoni, and then met the ancient enclosure.
It is not clear what happened to the northern front of the walls; these could have followed the Byzantine line, but according to some could have included Santa Reparata (Piazza del Duomo).
While no visible marks remain, it seems that this circle regained much of the perimeter of the first circle.
The Fourth Circle
In the 9th century, the city rapidly grew and the river port regained a great importance. By mid-century, it is estimated that the population grew to 20,000 inhabitants.
In this time of great demographic, political, and social awakening, the Countess Matilda di Canossa, fearing an Imperial siege, extended the town walls to include her extramural palace, thereby reoccupying the area of the Roman Gate.
Essentially, the new circle consisted of a strengthening of the previous one with the addition of the religious complex of the baptistery and of Santa Reparata, and the addition of the Castello d’Altafonte, situated on the river at defence of the port.
Reinforced in 1082, Florence withstood the siege of Emperor Henry IV for 10 days.
The fourth circle is also called the “ancient circle,” mentioned by the poet Dante Alighieri in the XV canto of Paradise in the Divine Comedy.
In the famous episode, the poet finds himself in the sky of Mars, home to the spirits of those fighting for the faith. Here he meets his great-grandfather Cacciaguida, who indulges in praise of ancient Florence, a city not yet bloodied by internal strife and economic turmoil.
The Fifth Circle
From the beginning of the 12th century, these walls were no longer sufficient, given that villages grew and became more crowded. Moreover, many villages came about across the Arno, which led to military and logistic problems.
When the Comune of Florence conquered this districts, a new defensive enclosure was planned to include the new suburbs and to prevent the feudal punitive expeditions. At the time, there was war between the city states and the feudal power, due to the descent in Italy of the emperor Frederick Barbarossa.
In the years 1172-1175, the city government decided to build the fifth city wall: for the first time, the Church of San Lorenzo was included in the walls, and a defensive wall was built in Oltrarno due to the increasing importance of the dwellings around the churches of San Felice, San Jacopo in Soprarno, and Santa Felicita.
Three city gates were built in Oltrarno (near today’s Piazza San Felice, Costa de’ Magnoli, and Piazza Frescobaldi), but protection consisted of palisades connecting the gates and houses whose outer façades were built without windows to offer more protection.
At the beginning of the 13th century, Florence was comprised of about 50,000 inhabitants, which grew to approximately 75,000 in the middle of that century, and to about 100,000 by the end of that century. Defensive and hygienic issues required the introduction, for the first time in a medieval city state, of a policy of urban planning. A new enclosure was also necessary.
The Sixth Circle
In 1284, the sixth circle was planned by the consultant of the architect Arnolfo di Cambio and was assisted by other famous artists such as Giotto.
The real work only started in 1298 and proceeded slowly and irregularly.
The main gates (Porta La Croce, Porta San Gallo, Porta al Prato) were first built, with completion of the walls in 1333. The quarters of Oltrarno finally received full protection.
These walls enclosed a very wide area (630 hectares) and protected the whole city, with its new outer dwellings. The perimeter was about 8,5 kilometres long, and the gates were 35 meters tall and were decorated with religious frescoes (the Madonna and Saints). Originally, on the square in front of each gate was also a statue of a famous Florentine writer or poet. These walls were in practice an expansion of the fifth enclosure because the streets of new suburbs followed the previous ones that broke away from the Roman nucleus.
Unfortunately, the Black Death of 1348 in Florence had effects similar to those it had in all of Europe. In fact, in 1348 Florence had approximately 80,0000 inhabitants but in just two years, the population was reduced to around 25-30,000 people.
Oversized for centuries, these walls enclosed large, green areas destined to urbanization, and were the location of the magnificent Renaissance gardens.
In 16th century, all city gates were pollarded (with exception of the gate of San Niccolò) to make them less vulnerable to artillery. When the city prepared itself to face the army of the German Emperor Charles V in 1530, new fortifications were added around the Church of San Miniato al Monte.
After that, Grand-duke Ferdinando I commissioned Bernardo Buontalenti with the building of a fortress known as Fortress of Belvedere.
Between 1865 and 1871, Florence was the provisory Capital of Italy: the city walls were demolished to build the new ring road, Viali di Circonvallazione. The man responsible of this work was the architect Giuseppe Poggi.
Only the walls in Oltrarno survived, with all their towers.