LETTER  OF  MARQUE
 

1. A letter of marque was an official commission issued by the Admiral of France authorizing a private ship to make war on behalf of the King. The private ship, the Captain and the crew were known as "Privateers".

Click here to display a typical letter of marque

 
 

2. As soon as the privateer Captain has received his letter of marque, he must register it at the record office of the nearest Admiralty.


 

3. When a privateer is made prisoner by the enemy he is treated as a prisoner of war due to his letter of marque.

I am assuming that was the case of Francis Lebaron