It is also scarcely mentioned in the Low Middle Ages: Charlemagne donated to one of his captains a "Castle of Signa", although this is disputed.

[4] Signa acquired local importance in the 14th century after the construction of a nearby bridge, the only one in the area allowing passage of the Arno river.

It was conquered by condottiero Castruccio Castracani and is also mentioned in Dante Alighieri's Divine Comedy.

On the day after Easter, there is an important religious festival in honour of the Beata Giovanna.

Other natives include the artists Bruno Catarzi, Giuseppe Santelli, Raffaello Fossi, Alimondo Ciampi, and Alvaro Cartei; the academics Tommaso Bisagno and Boncompagno da Signa; Blessed Giovanna da Signa; the journalist Piergiorgio Branzi; and the actor Giancarlo Gori.