Palermo is the first city of Sicily in size and importance. The ancient Panormos, built in the eighth century BC., Has Phoenician origin; developed on a hill elliptical, bordered by two rivers to the north and south and wet from the sea to the northeast. The first core surrounded by walls spread to the area currently affected by the Norman Palace, Piazza della Vittoria and the Archbishop's Palace, and later the houses stretched towards the sea. This new city, called Cassaro, was equipped with walls, together with the original walls in a single defensive system. The city passed into the hands Carthaginian and Roman times until, in the ninth century, it was conquered by the Arabs who increased the prestige, promoting their development. The Norman conquest of 1072 did not erase the cultural influences of Arab, Byzantine and Latin, but united them to shape beautiful monuments, architectural synthesis of different cultures. Palatine Chapel, for example, adorned with magnificent mosaics, blends Romanesque, Byzantine and Arab, in the Martorana, architectural jewel of the Norman period, we recognize the influence of Byzantine art, the Cathedral of San Cataldo retains some elements of Arab, also evident in the beautiful complex of St. John of the Hermits. In 600, however, there was a radical change in the planning of Palermo. By the will of the viceroy, in fact, were built new palaces, churches, monasteries and fountains, valuable evidence of the Baroque Palermo, and is called the present appearance of the city.