[3] It was assumed that Calascibetta was founded in the 9th century as a Muslim military camp, on the fortress in front of Henna, to attempt the siege of the Byzantine stronghold.

Frequented in the Byzantine era as evidenced by nineteenth-century documents relating to frescoed caves used by Basilian eremitic monks, it is believed that a real foundation of Calascibetta took place with the Norman conquest of the island, where it appears mentioned in 1062, when it was fortified by Roger I, who had built the castle called "Marco", the first walls, the first village, during the siege of Castrogiovanni, and the great cathedral dedicating it to the Virgin Mary and to the Apostle St. Peter.

Unlike many of the small towns in Sicily, Calascibetta remained a city owned by the central royal government, and not a private feudal property.

As such, it experienced a period of unmatched splendor, favored and preferred as it was by the Aragonese kings, including Peter II who died there during a stay, who endowed it, following the example of the Normans, with churches and monuments.

In 1492, Calascibetta was one of about 50 towns in Sicily which included a giudecca, or a Jewish urban neighborhood, typically now labeled as a ghetto.