The town of San Giovanni Valdarno is in the province of Arezzo and has about 17000 inhabitants. This town, which was founded in the XIII century by Florence, is rich in art. The Basilica and its museum can be visited, as well as Palazzo d'Arnolfo and Casa Masaccio. Moreover, its old city centre in a medieval style is very suggestive.

As said above, San Giovanni Valdarno is one of the "new lands" founded by the Florentines around the end of the XIII century, in order to consolidate their presence in the Upper Valdarno. The building of the town dates to 1296.
Three years later, a decree forbade to the aristocratic families to cross the town's walls. This happened because the then Guelf-ruled Florence had been fighting against the local nobles and the feudatories of the Empire, all Ghibellines, for years.
Many inhabitants of the Valdarno went to live in San Giovanni in exchange for tax exemptions, and they provided for the building of their houses and for carrying out fortification works. Numerous episodes of attacks by the anti-Florentine parties delayed the construction of the town's walls. Between 1356 and 1363, the town underwent a new cycle of reinforcement works that ended with the construction of many towers (twenty-four) for protecting the walls.
In 1401 the city became the seat of the Valdarno's vicariate. Even though the fights with Arezzo had come to an end, San Giovanni was militarily important in the following conflicts between Florence and the Visconti from Milan. The Visconti's troops headed by the leader Niccolò Piccinino carried out numerous incursions in the Valdarno before the Republic's army could drive them away one more time after the famous battle of Anghiari in 1440.
Later, in 1478, Sixtus V's troops were those who defeated the defences of San Giovanni. The following year, the plague appeared, too.
In the XVI century, the town's function as a military garrison disappeared and the Florentine bourgeoisie's investments in the town diminished, too. The town's walls, that the Arno's floods had been continuously damaged, were not subjected to any further recovery work. The town's decadence eventually stopped in the second half of the XVIII century, when Pietro Leopoldo of Lorraine was ruling the Tuscan Grand Duchy. Thanks to him, San Giovanni, which had become an autonomous "comunitas" between 1772 and 1773, was the object of investments and of a policy of rearrangement of the river with the object to encourage the local agriculture. In 1848, San Giovanni was assigned to the province of Arezzo, a decision that was confirmed after the Unity of Italy, too, in spite of its citizens' reiterated protests.