From Tri Synergy:
Port Royale takes place in one of the most exciting seagoing settings for a game: the pirate-infested Caribbean of the 16th and 17th centuries. At the time, huge Spanish galleons loaded with gold carried enough cannons to keep ordinary pirates at bay, but there were still plenty of less-defended trade ships that were easy prey for dastardly pirates and buccaneers looking to amass a quick fortune. Intermittent wars between colonial nations made this frontier even wilder--well-armed traders would often be pressed into duty as privateers with a license to sink or capture enemy ships. Port Royale sets you loose in the middle of this world to make your way as a trader, privateer, pirate, or some combination of the three. Once you get past Port Royale's steep learning curve, you may find yourself enthralled by the game's promise of profiteering and pirating on the high seas.