We know with certainty that this place existed in the first Christian cathedral of the city in the fourth century, although we are not sure if today's church is something of this.
In the ninth century with the arrival of the Saracens it was transformed into a mosque.
The Normans wanted to build here the capital of their kingdom; a magnificent cathedral would represent their power and their Christianity. So works began in Monreale, but at the same time with them here, too, led by the archbishop Gualtiero Offamilio when he had given the ground symbolically the mosque.

The interior testifies strong influence of religious sensibilities, northern European and Byzantine architecture, and worked out teachers from Arabic, so it is natural that while the form with the double tower is typical of the Norman cathedrals of France and England.
The decoration in the details of the implementation contains many elements that could arise even from mosques.
In 700 it was commissioned on the rebuilding of the cathedral, it has been entrusted to escape, but Ferdinand was performed during the nineteenth century by Marvuglia.
His modifications were actually much more invasive and radical projects of the Florentine architect. The apse is squeezed between the towers is the most original of the twelfth century, the south-west facade, which looks at the archbishop's residence, should be reported to the fourteenth and fifteenth centuries.

To testify the importance of the royal tombs of the cathedral: Frederick II is buried here and his wife, Henry IV and the first king of Sicily, Roger II. To the right of the presbytery is the chapel of Santa Rosalia, patron saint of Palermo, silver urn containing the relics, the Cathedral and its square are the protagonists of his party sites.