the city was away from the coast. Currently, it is located from the coast. However, it was a maritime city, with ships sailing up the Arno. In the 90s AD, a baths complex was built in the city. Late Antiquity and Early Middle Ages During the last years of the Western Roman Empire, Pisa did not decline as much as the other cities of Italy, probably due to the complexity of its river system and its consequent ease of defence. In the seventh century, Pisa helped Pope Gregory I by supplying numerous ships in his military expedition against the Byzantines of Ravenna: Pisa was the sole Byzantine centre of Tuscia to fall peacefully in Lombard hands, through assimilation with the neighbouring region where their trading interests were prevalent. Pisa began in this way its rise to the role of main port of the Upper Tyrrhenian Sea and became the main trading centre between Tuscany and Corsica, Sardinia, and the southern coasts of France and Spain. After Charlemagne had defeated the Lombards under the command of Desiderius in 774, Pisa went through a crisis, but soon recovered. Politically, it became part of the duchy of Lucca. In 860, Pisa was captured by vikings led by Björn Ironside. In 930, Pisa became the county centre (status it maintained until the arrival of Otto I) within the mark of Tuscia. Lucca was the capital but Pisa was the most important city, as in the middle of tenth century Liutprand of Cremona, bishop of Cremona, called Pisa ("capital of the province of Tuscia"), and a century later, the marquis of Tuscia was commonly referred to as "marquis of Pisa". In 1003, Pisa was the protagonist of the first communal war in Italy, against Lucca. From the naval point of view, since the ninth century, the emergence of the Saracen pirates urged the city to expand its fleet; in the following years, this fleet gave the town an opportunity for more expansion. In 828, Pisan ships assaulted the coast of North Africa. In 871, they took part in the defence of Salerno from the Saracens. In 970, they gave also strong support to Otto I's expedition, defeating a Byzantine fleet in front of Calabrese coasts. 11th century The power of Pisa as a maritime nation began to grow and reached its apex in the 11th century, when it acquired traditional fame as one of the