Originally, the town was called San Giovanni di Cammarata due to the closeness of the eponymous mountain. In 1879, the name was changed into San Giovanni Gemini after the two equally high hills in the area known as "i gemelli" (twins). The town was founded in 1451 by the Count of Cammarata, Federico Abbatelli Chiaramonte when he obtained the privilege of building new lands (
Ius aedificandi); it wasn't until 1507, though, that he obtained from
King Ferdinand II of Aragon permission to populate the land (
licentia populandi) San Giovanni was elevated to a duchy by Count Ercole Branciforte, who was invested with the title of duke by
King Philip II of Spain; the royal privilege was granted on 10 November 1587 and made official in Palermo on 15 May 1588. Under his ownership, the duchy underwent a substantial economic and demographic growth which led him to separate the territory into two parts named Cammarata and San Giovanni. The Duchy of San Giovanni passed as a dowry to the Moncada family in 1666 following the marriage in that year of Duchess Giovanna Branciforte Moncada (1645-1680). She was invested as the owner of the fiefdom on 18 February 1656 alongside her maternal uncle Ferdinando Moncada Gaetani, son of Ignazio of the princes of Paternò. In 1708, the town was bestowed to Count don Luigi Moncada, whose family ruled San Giovanni and Cammarata until the abolition of feudality in 1812, the year when feudalism was abolished in Sicily. The abolition was a result of the new Sicilian Constitution granted by
King Ferdinand III of Bourbon. ==Industry==