Prize [pɹɑɪz] is a term used in admiralty law to refer to equipment, vehicles, vessels, and cargo captured during armed conflict. The most common use of prize in this sense is the capture of an enemy ship and its cargo as a prize of war. In the past, the capturing force would commonly be allotted a share of the worth of the captured prize. Nations often granted letters of marque that would entitle private parties to capture enemy property, usually ships. Once the ship was secured on friendly territory, it would be made the subject of a prize case, an in rem proceeding in which the court determined the status of the condemned property and the manner in which it was to be disposed of.
At the outset, prize taking was all smash and grab "like breaking a jeweler's window," but by the fifteenth century a body of guiding rules, the maritime law of nations, had begun to evolve. Grotius's seminal treatise on international law published in 1604 called De Iure Praedae Commentarius (Commentary on the Law of Prize and Booty) (of which Chapter 12, "Mare Liberum" inter alia founded the doctrine of freedom of the seas) was an advocate's brief justifying Dutch seizures of Spanish and Portuguese shipping. Grotius defends the practice of taking prizes as not merely traditional or customary but just. His Commentary points out that the etymology of the name of the Greek war god Ares was the verb "to seize;" that the law of nations had deemed looting enemy property legal since the beginning of Western recorded history in Homeric times.