The origins of Pisa are still unknown. Some historians affirm that it was founded during a very old era, a great deal older than Rome and the most important european sea-cities. It is estimated that the city was founded between the 7^th and the 6^th century B.C. by the Greeks or the Ligurians. What is well known, that during the 5^th century B.C. Pisa was occupied by the Etruscans. From its origins Pisa has gone from strenght to strenght thanks to the fertile territory that had provided the population with several kind of goods and products. But the main benefits were given by the navigation, in fact Pisans were able to establish intense commercial exchanges with foreign countries of occidental Mediterranean sea and later also to oriental routes. Owing to the growth of Roman Empire, etruscan Pisa had established an alliance and later prefered to pass under control of Rome. Pisa had always given considerable help to the Empire supplying it with soldiers and ships, especially while the war against Carthage. It was during this period that the city had its stronger growth thanks to the sustenance and protection of Rome. Pisa became one of the most important sea city of the Mediterranean sea after the Roman Emperor had given orders to build in the city the most important roman port and some shipyards able to build ships of good quality.