Choice of Law in International Commercial Arbitration

It has become common to speak of international "commercial" arbitration, but there is no clear concept of what is meant by "commercial". As early as the 1923 Protocol on Arbitration Clauses, Contracting States recognized the validity of an arbitration clause "by which the parties to a contract agree to submit to arbitration all or any differences that may arise in connection with such contract relating to commercial matters or to any other matter capable of settlement by arbitration, … ."