The document summarizes key events in the struggle for power in the Mediterranean Sea between the Ottoman Empire led by Sultan Suleiman and the Holy Roman Empire led by Charles V in the 1500s. It describes the Siege of Rhodes by the Ottomans, which forced the Knights of Saint John to retreat. It then discusses the Barbarossa brothers who led corsair fleets against the Spanish coast until Charles defeated one brother and the other joined the Ottomans. Finally, it notes Charles hired Admiral Andrea Doria to help strike back against Suleiman and the Ottoman commander Hayrettin on the Grecian coast.