LAW MERCHANT or LEX MERCATORIA, originally a body of rules and principles relating to merchants and mercantile transactions, laid down by merchants themselves for the purpose of regulating their dealings. It was composed of such usages and customs as were common to merchants and traders in all parts of Europe, varied slightly in different localities by special peculiarities. The law merchant owed its origin to the fact that the civil law was not sufficiently responsive to the growing demands of commerce, as well as to the fact that trade in premedieval times was practically in the hands of those who might be termed cosmopolitan merchants, who wanted a prompt and effective jurisdiction. It was administered for the most part in special courts, such as those of the gilds in Italy, or the fair courts of Germany and France, or as in England, in courts of the staple or piepowder (see also SEA LAWS). The history of the law merchant in England is divided into three stages: the first prior to the time of Coke, when it was a special kind of law as distinct from the common law administered in special courts for a special class of the community (i.e. the mercantile); the second stage was one of transition, the law merchant being administered in the common law courts, but as a body of customs, to be proved as a fact in each individual case of doubt; the third stage, which has continued to the present day, dates from the presidency over the king's bench of Lord Mansfield (<?..), under whom it was moulded into the mercantile law of to-day. To the law merchant modern English law owes the fundamental principles in the law of partnership, negotiable instruments and trade marks.
See G. Malynes, Consuetudo vel lex mercatoria (London, 1622); W. Mitchell, The Early History of the Law Merchant (Cambridge, I 94); J- W. Smith, Mercantile Law (ed. Hart and Simey, 1905).
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)