Privateers were private individuals or ships authorized by a government to attack enemy vessels during wartime. They operated under a document called a letter of marque, which allowed them to capture enemy ships and claim their cargo as prizes. This practice was common from the 16th to the 19th centuries, especially during conflicts like the American Revolutionary War and the Napoleonic Wars. Unlike pirates, who acted independently and unlawfully, privateers had the backing of their government, making their actions legal. The captured ships and goods were often shared with the government, providing a financial incentive for privateering. This practice contributed to naval warfare and commerce during its time.