The stage for naval warfare in the last centuries of the Middle Ages was set by economic and political changes in the two hundred years before 1200. The considerable growth in productive activity in the period was most obvious in the expansion of seaborne trade, Italian port cities being among the greatest beneficiaries. Their commercial success yielded not only prosperity but also more aggressive maritime strategies. Christian conquests in Sicily, Spain and the Levant shifted the naval frontier. Taking strategic points along major trading routes gave Christians an advantage in all the naval wars against Muslims. Twelfth-century improvements meant that ships from Christian ports could make voyages from one end of the Mediterranean to the other without stopping. A constellation of technical changes opened the door to an expansion of trade and of naval operations. Longer voyages, increased frequency and longer sailing seasons, relying on the compass, books of nautical instructions and maps, made both war and cargo ships more effective.

The 1204 Venetian conquest, with the aid of northern crusaders, of Constantinople changed the naval context. Formerly a thalassocracy and dominant naval power, the Byzantine Empire became Latin Christian and an unstable ally of Venice. The maritime republic committed to creating its own thalassocracy. 1204 marked the birth of the Venetian maritime empire with stations in the eastern Mediterranean. A rivalry had already emerged among Italian port towns, especially over access to lucrative trades in the Levant and Black Sea. Competition over commerce drove the naval policy of the maritime republics and other states as well.