Background

From the thirteenth century the development of English overseas trade made necessary a body of laws to regulate commerce which, reflecting the practices of the markets, would be acceptable to denizen and alien merchants and shipmasters. Common law was peculiar to England and had grown out of customary usage; merchant law, on the other hand, had developed from the Roman corpus juris and was accepted, with local variations, throughout the rest of Europe. Merchant law followed the concept that the sea was outwith national jurisdiction, or nullius territorium, and was described by a fifteenth-century English chancellor as ‘secundum legem naturam qu'est appell par ascuns ley Marchant, que est ley universal per tout le monde’ (‘following natural law which is called by some Merchant Law which is the universal law for the whole world’). In addition to common and merchant law, for problems which arose aboard ship or between one ship and another, mariners were subject to maritime law, a code of international application derived from the sea laws of the classical Mediterranean states and related to merchant law. For felonies committed ashore or at sea, mariners, as any other person, were subject to criminal law.

In late medieval England, these and other legal codes in use were the result of disparate decisions handed down by a bewildering diversity of courts, each reflecting the differing expectations and needs of a section of society.