Pirate or Privateer

From the 16th to early 19th centuries "Privateers" were the mother countries legal pirates given "Letters of Marque" that allowed them to prey on the merchant shipping of "enemy" nations. Such commerce raiding was lucrative for both the privateers who provided their own ships and crews and for the navy that added to their commerce raiders at no expense to the naval budget.  

The object of a privateer was to capture their victims, man them with a "prize crew," and sell the ship and cargo at a friendly port. The government that granted the "Letters of Marque" most often received a percentage of this "prize money." Be they the "Seadogs" of England's Elizabeth I or American adventures of the Revolutionary War and War of 1812, privateers were more often seen as legal pirates by the merchants they pounced upon on the high seas.