During the 1160s an adventurous rabbi named Benjamin of Tudela set out from Zaragoza in the upper Ebro Valley on an ambitious journey that would eventually take him to the eastern rim of the Mediterranean and beyond to distant Khurasan. After several days sailing down the broad, slow–moving Ebro and skirting the beaches and rugged hills of the Catalan coast on the first leg of his trip, he arrived at Barcelona. When he described the city many years later in his travel log, Benjamin, by then a seasoned traveler thoroughly conversant with the nuanced idioms of Mediterranean urban life, recalled it as a small but dynamic port, attracting merchants from Genoa, Pisa, Sicily, Alexandria, Greece, and the Levant. Although neither as self–assured or domineering as the bustling Italian communes nor as cosmopolitan as the exotic Greek and Islamic cities he had visited, Barcelona nevertheless seemed to him full of energy and promise. Benjamin of Tudela's terse description captured a medieval city undergoing rapid transformation.

During the twelfth century the maritime powers of the Latin Mediterranean were vying to dominate the sea lanes that Christian galleys had secured from Islamic attacks. As the lines of commercial, naval, and diplomatic communication grew denser among cities on or in contact with the coasts of Italy, Occitania, and Catalonia, patterns of cooperation and competition emerged that would leave their imprint on the rest of the Middle Ages and beyond.