The old city centre of Palermo, with its area of over 240 hectares - about one square mile - is one of the largest in Europe and also one of the richest and most varied. It contains over 500 palaces, churches, convents, and monasteries, plus seven theatres. The city has steadily expanded since the period of Phoenician colonisation, with successive waves of Greeks, Romans, Byzantines, Arabs, Swabians, Normans, and Spaniards, until the more recent town-planning initiatives in the nineteenth and early twentieth centuries. As a result, Palermo is extremely variegated and complex in its layout, although it has also succeeded in maintaining a clearly recognisable overall uniformity of structure and character.
Traditionally divided into four separate quarters, the old city has its centre in the octagonal Piazza Vigliena (better known as Quattro Canti di Città), the geometric and symbolic heart of the city. This square was laid out in the 17th century, when Via Maqueda was constructed bisecting the old thoroughfare known as the Cassaro, now renamed Corso Vittorio Emanuele.
Immediately adjacent stands the Cathedral, dedicated to the Most Holy Mary of the Assumption, with its spectacular and imposing façade, separated from the Cassaro by a flat open space.
Built by the Normans on the exact spot where in early Christian times stood a sanctuary (later transformed into a Christian basilica and then an Arab mosque), the building has undergone some drastic transformations in the course of the centuries. The most important of these works date from the 15th and 16th centuries, when the beautiful southern portico in Catalan-Gothic style was created (1453), and the 18th century, when the cupola was added. The vast interior, now in neoclassical style, conserves the sarcophagus of Frederick II, together with those of Roger, Henry VI, and Constance of Hauteville, as well as numerous works of art, including a silver urn with relics of Santa Rosalia, Palermo's patron Saint.
