In 810, when the Franks replaced the Lombards as the rulers over much of Italy, they too attempted to conquer the coastal area including Venice. But the marshes and lagoons were too much for them, and in addition, the Byzantine emperor sent a fleet to the support of his province. By now, Venice had become immensely important to Byzantium as its main outlet in the West, made ever more significant as Islam developed a trading network throughout the region, including Spain, Sicily, and the toe of Italy, along with North Africa.
