Lex mercatoria is the Latin expression for a body of trading principles used by merchants throughout Europe in the medieval. Meaning literally "law merchant", it evolved 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 law of commerce.It emphasised contractual freedom, alienability of property, while shunning legal technicalities and deciding cases ex aequo et bono.A distinct feature was the reliance by merchants on a legal system developed and administered by them. States or local authorities seldom interfered, and surrendered some of the control over trade within their territory to the merchants. In return, trade flourished under the lex mercatoria, increasing tax revenues.