The construction of the "Duomo" began in 1064 by the architect Busketo, who with this structure set the model for the distinctive Pisan Romanesque style of architecture.

The façade, seen here from the gallery of the baptistry, was built by master Rainaldo. Just like Diotisalvi, who had designed the baptistry he had designed, Reinaldo signed the facade over the center door "Rainaldus prudens operator".

Above the doors there are four rows of open galleries with, on top, statues of Madonna with Child and, on the corners, the Four evangelists.

When the construction of this cathedral started, Pisa was on a height of political (and financial) power. Pisa was an important commercial centre controlling large parts of the Mediterranean merchant fleet and navy.

In 1017 Pisa had militarily supported the Sardinian "Giudicati" (regional kings) to defeat Saracen troops in the north of Sardinia. Between 1030 and 1035, Pisa defeated rival towns in Sicily. In 1051–1052 admiral Jacopo Ciurini conquered Corsica. In 1063 admiral Giovanni Orlando, coming to the aid of the Norman Roger I, took Palermo from the Saracen. The gold treasure taken from the Saracens in Palermo allowed the Pisans to start the building of the cathedral - and all other building of the "Piazza del Duomo".