Ever since the early days of navigation, the sea offered a source of income to pirates. In antiquity, the distinction between piracy and the hostilities of sea battles in general was not always clear and this confusion continues until almost today. The means and methods of piracy, as well as pirates’ strongholds have not essentially changed throughout the centuries. When a nation seek to suppress piracy and to master the seas it should be politically and economically strong, as the examples of Crete, Athens and Rhodes can prove. Attention should also be paid to the relation between pirates and mercenaries at sea and to the financial and geographic causes that have produced these phenomena.