In the 9th century, the Arabs built a palace for their Emir, and under the Norman rulers and the Hohenstaufen Frederick II, the palace became even more splendid.
It suffered a long period of neglect, until the Spanish viceroy renovated and extended it to use as his residence. Since 1947, the regional parliament of Sicily has sat here.
One prominent Norman structure remains on the northeast front, the high Torre Pisana with its neat square stone blocks and blind arcades of ogival arches.
It is the last remaining of the original four towers; inside is a typical square hall, above which an observatory was built in 1791.
