Since the Middle Ages, the municipality of Signa was of great historical importance because of its strategic position. It is also an interesting area in terms of culture and art. The town is comprised of a low-lying part, which extends along the Arno river, and an ancient center that is found on higher ground, called "Castello".
The ancient core of the city was established before 1000 AD, and it has a surrounding wall with fourteen-century doors. Signa’s main churches are located in Castello, like for example, Santa Maria in Castello church, San Giovanni Battista church (where the remains of the town’s patron, Beata Giovanni are located), San Lorenzo church and San Miniato church.
The municipal territory is approximately 19 km squared, making it the smallest township in the province of Florence. Signa is located in the spot where three rivers converge: the Ombrone Pistoiese, Bisenzio and Arno rivers.
The origin of Signa and the years in which it was first established is unknown thanks to the small amount of historical documentation available on this town. Thus, there are several theories that collocate the birth of Signa to some time in the period spanning the end of Etruscan age and the beginning of the Roman age. More recently, scholars have affirmed that the former is the most probable, thanks to its location along the Pisa-Fiesole route, which contributed very much to its growth and further development. It seems that the town of Signa was established for commercial needs, thanks to its proximity to the Arno, it was logistically advantageous, especially because the trajectory between Signa and Pisa was the only available transport route along the Arno in the summer months.
There are many doubts on the etymological origins of the word ‘Signa’. If the town was founded by the Etruscans, then probable names would be Aisinial, Eisil and Esinius; if it was founded by the Romans, then it was most likely called Exine, Exinea, Esinea and Sinea. Recent studies show that the former hypothesis is probably the most likely. Etymologically, Signa most likely derived from the name Aisinius, which can be attributed to the town’s founder, a man named Lucio Cornelio Silla, who allocated much land in this area by way of an ‘eredium’, a law which foresaw that each Roman citizen, especially Roman soldiers, were given a plot of land to cultivate and raise their own livestock.
Other documents that attest to Roman colonization in Signa where discovered in archeological digs in Renai Park and from several tombs located in the church of San Lorenzo. Although, scholars do not deny that this area was once colonized by the Etruscans, as the Bronzetti tombs located along the municipal border of Carmignano and Signa would suggest, the Roman origins of Signa can be further attested to by a plaque in the church of San Giovanni Battista. Regarding its Roman origins, other theories take into account the original foundations of the town. Many accredit Roman consul Tito Quinto Flaminio as one of the town’s founders, while others believe that Signa was born from a Roman encampment, just like how Florence was founded.