An ancient authority to arm a private warship
In olden times, Kingdoms and governments did not have navies. They would license private ships (privateers) To capture their enemies’ shipping and goods. These licenses were called Letters of Marque and have been issued by all the major seafaring nations since the thirteenth century.
Privateers sailed under the protection of Letters of Marque. They were privately owned warships commissioned by a belligerent nation to carry-on naval warfare for profit. The captured ships, booty and plunder would be divided between the issuing government, the vessel’s owner, and her crew. It was legal piracy. In the 18th century 365 Letters of Marque were issued from just Boston alone.
Privateering is distinguished from piracy because piracy is carried on without enlistment by a government (Letters of Marque). Because pirates did not carry Letters of Marque—they would be hanged. Privateers were not hanged. They were usually held for ransom or imprisoned when their ships were captured. The last conviction for piracy in the USA was in 1819.