Letter of marque
A letter of marque and reprisal was a government license in the Age of Sail that authorized a private person, known as a privateer or corsair, to attack and capture vessels of a foreign state at war with the issuer, licensing international military operations against a specified enemy as reprisal for a previous attack or injury. Captured naval prizes were judged before the government's admiralty court for condemnation and transfer of ownership to the privateer.