The Ottoman Empire used impalement during, and before, the last siege of Constantinople in 1453. During the buildup phase to the great siege the year before, in 1452, the sultan declared that all ships sailing up or down through the Bosphorus had to anchor at his fortress there, for inspection. One Venetian captain, Antonio Rizzo, sought to defy the ban, but his ship was hit by a cannonball. He and his crew were picked up from the waters, the crew members to be beheaded (or sawn asunder according to Niccolò Barbaro), whereas Rizzo was impaled. In the early days of the siege in May 1453, contingents of the Ottoman army made mop-up operations at minor fortifications like Therapia and Studium. The surrendered soldiers, some 40 individuals from each place, were impaled.