Frederick’s Teutonic Knights, joining forces with the army of Pavia, finally laid siege to hated Alessandria, which, newly founded, was protected only by a large moat, no walls. As usual, the Germans lacked the technical expertise and craftsmen to build siege engines, so Frederick appealed to Genoa for help, which provided engineers and laborers, as well as contingents of crossbowmen, paid in cash. Alessandria’s warehouses, however, were already full of supplies, as the siege had been launched too late in the season.
