The Vienna Convention is limited to written treaties in the interest of clarity and simplicity,without denying the legal validity of oral agreements. An agreement, to be termed as a treaty, should be governed by international law and not by national law. Like terminology, international law does not prescribe any form or procedure for the making of a treaty, though the constitutional law of certain states prescribes both. Only the entities enjoying international legal personality can be parties to a treaty. Article 6 of the Vienna Convention provides that “every state possesses capacity to conclude treaties.”