A letter of marque and reprisal was the paper that separated a privateer from a pirate: carry it and you were a prisoner of war with a lawyer, lose it and you were hostis humani generis, an enemy of mankind bound for the gallows. Henry III issued early commissions around 1243 and the first documented letter appeared under Edward I in 1295, letting a robbed merchant recover his exact losses from the offending nation. By the 16th century governments used them to outsource naval war, with private owners supplying ships, powder, and crews in exchange for prizes. The system ran on bureaucracy: applicants listed tonnage and every cannon, British captains posted bonds of around 1,500 pounds, and every captured ship had to be sailed to an admiralty court and legally condemned before auction.

Profits were huge. Guernsey privateers took French and American ships worth over 125 million pounds in today’s money during the American Revolution, Elizabethan voyages by Francis Drake and Walter Raleigh were funded by plunder, and the East India Company armed ships such as the Royal Charlotte and Triton with letters of marque. The 1856 Declaration of Paris abolished privateering, but the United States refused to sign, and Article 1, Section 8 of the Constitution still lets Congress issue letters of marque. Lawmakers keep reviving the idea against terrorists after September 11, Somali pirates in 2009, Russian oligarchs’ yachts in 2022, and Mexican cartels in a December 2025 bill from Senator Mike Lee.

• A letter of marque also named a slow armed cargo ship that carried the paperwork in case an enemy crossed its path.
• Captain Luke Ryan and his lieutenants sailed under the flags of three countries in a single conflict.
• The Lafitte brothers of New Orleans bribed unstable new governments for commissions to cover a smuggling empire.
• William Kidd held a legitimate commission yet was hanged for piracy and left in a gibbet over the Thames.
• The rumor that World War II Goodyear blimps like the Resolute flew as privateers was false.