Designed by Raphael but executed with the assistance of his pupils Giulio Romano and Giovanni da Udine, who was responsible mainly for the architecture and ships in the background, this fresco depicts an event that occurred during the pontificate of Leo IV. In 849, Saracen pirates appeared off Ostia and threatened to advance up the Tiber estuary to Rome. With the help of galleys from Naples, Amalfi, and Gaeta, the pope's fleet was victorious against the assailants. In the background we see the final phase of the eventful battle, when the Saracens, identifiable by their turbans, are facing defeat, symbolized by the sinking ship in the middle ground. In the foreground, Saracen prisoners are led before Leo IV, enthroned on the left with cardinals and clergymen, who thanks God for His help. The Saracens, shown in contorted positions being treated brutally, are masterpieces of nude painting and demonstrate the talent of the young Giulio Romano. The topical relevance of the fresco was a Turkish threat that Leo X was planning to counter with a crusade.