Map - San Casciano in Val di Pesa (San Casciano in Val di Pesa)

San Casciano in Val di Pesa is a comune (municipality) in the Metropolitan City of Florence in the Italian region Tuscany, located about 15 km southwest of Florence.

San Casciano in Val di Pesa borders the following municipalities; Greve in Chianti, Impruneta, Montespertoli, Scandicci and Tavarnelle Val di Pesa.

San Casciano’s territory was inhabited since Etruscan times, as evidenced by archaeological findings in Montefiridolfi (The Bowman’s Grave) and Valigondoli (Poggio La Croce’s excavations). In Roman times San Casciano was a post-stage (mansio) posted at the tenth mile from Florentia. The toponym "Decimo" (i.e. tenth) is still attached to the Pieve di Santa Cecilia a Decimo (a parish church near San Casciano which was mentioned in 1043 in a document and commemorates a milestone (decimum lapidem) on an important Roman road (probably that linking Florentia and Sena Julia). Archaeological findings and toponymic evidence are clear evidence of the town’s antiquity, and that there was a significant population is indicated by the large number of parish churches in the area (e.g. Pieve di Santa Cecilia a Decimo, Pieve di San Pancrazio, Pieve di San Giovanni in Sugana and Pieve di Santo Stefano a Campoli), not to mention the significant number of subordinate churches. There is little doubt that the area was still densely populated in the Middle Ages, based upon the many castles which were built at the time for the bishopric of Florence or powerful families like the Buondelmonti or Cavalcanti.

San Casciano was originally mentioned as a fief of the Bishop of Florence, who made its first statutes in 1241. In 1278, the domain shifted to the Republic of Florence. A few years later San Casciano became the capital of a local alliance, including the Alliance of Campoli, and the seat of a podestà, therefore having the government of forty parish churches. By 1325 San Casciano had become so important that a statute of the Florence podestà described one of the main roads departing from the city as follows: “strada per quam itur ad ‘"Sanctum Cassianum"’ (…) versus civitatem Senarum et versus romanam Curiam” (i.e. “the road going through San Casciano towards Siena and Rome”). That San Casciano's history is bound to its roads is shown also by its shape, which is in the form of a cross: one side going from Florence to Siena and the other, following the hills’ ridge, linking the Chianti area with Montelupo and the Arno river basin. Furthermore, a major role in San Casciano’s development was played by the improvement in agricultural productivity resulting from sharecropping, which led to population growth and the formation of commercial centres like Mercatale and the castle of San Casciano “a Decimo” itself.

The walls of this castle were built in the second half of the 14th century (and their ruins still exist today). Indeed, in the first half of the same century, San Casciano was completely undefended and therefore became an easy prey for condottieri and mercenary troops. San Casciano was occupied by the Holy Roman Emperor Henry VII from November 1312 to January 1313, the Duke of Lucca Castruccio Castracani in February 1325, and the French mercenary Moriale D'Albarno in July 1343. In consequence of these attacks, the Republic of Florence decided to fortify the village in 1354. The walls were in place by 1355 and, in addition, a “cassero” (i.e. a castle serving as barracks) was added in 1356.

A few years earlier, Walter VI of Brienne, Duke of Athens had planned to transform the village into a castle, to be called “Castel Ducale”, but the plan died with him. In 1494 Charles VIII of France camped near the village without entering it. Before his departure, he donated a large sum of money to the local Franciscan convent. In 1512 at the Albergaccio (near to Sant'Andrea in Percussina) Niccolò Machiavelli started his exile during which he wrote The Prince and The Mandrake. When the Grand Duchy of Tuscany rose to power, San Casciano lost its military and strategic role and its history followed that of Tuscany.

In 1893, after the annexation of the Grand Duchy of Tuscany to the Kingdom of Italy, a steam-engine railroad was built to link San Casciano and Florence.

On 26 July 1944, during World War II, San Casciano was almost entirely destroyed by an Allied bombardment. It has been slowly but finely reconstructed.