maritime law, system of law concerning navigation and overseas commerce. Because ships sail from nation to nation over seas no nation owns, nations need to seek agreement over customs related to shipping. From such agreements between nations has grown a body of customs and usages that is the basis for maritime law. It was, in origin, based on customs only, but it felt the influence of the Roman civil law. In the later Middle Ages, when traders were more and more venturous in crossing the waters, the rules of the sea were compiled into widely recognized collections such as the Consolato del mare [consulate of the sea], The Rolls of Oléron or The Laws of Oléron, and the English Black Book of the Admiralty. In England, special courts were set up to administer the law under the high court of admiralty. The Judicature Act of 1873 abolished these courts and assigned their functions to the high court of justice. In the United States the Constitution gives the federal courts authority in "all cases of admiralty and maritime jurisdiction." This jurisdiction covers all maritime contracts, torts, injuries or offenses, and questions of prize. In cases of collision at sea, the parties may under the Judiciary Act of 1789 bring suits at common law; otherwise all maritime cases come to the federal courts. The jurisdiction extends to all navigable waters of the United States, and much of the law is now governed by federal statutes. Though maritime law is general in character, only those parts that determine the relations among nations—particularly those that deal with problems arising on the seas in wartime, such as questions of belligerency and neutrality—are part of the international law proper. See admiralty; blockade; piracy; privateering; seas, freedom of the; London, Declaration of; Paris, Declaration of. See also sea, law of the.
See H. Reiff, The United States and the Treaty Law of the Sea (1959); R. P. Anand, The Origin and Development of the Law of the Sea (1983); R. R. Churchill and A. V. Lowe, The Law of the Sea (2d ed. 1988).