1) Customary legal system 
Lex mercatoria (from the Latin for `merchant law`) is the body of commercial law used by merchants throughout Europe during the medieval period. It evolved similar to English common law as a system of custom and best practice, which was enforced through a system of merchant courts along the main trade routes. It functioned as the international l.....
lex mercatoria [mercatoris] Law merchant. The body of law dealing with commercial traders and their transactions.