Rules regulating the various aspect of diplomatic relations are the result of centuries of States practice.  They constitute one of the earliest expressions of International Law. Whenever in history there have been independent States coexisting, special customs have developed on how the representatives of one State would be treated by other State.

          Today, diplomats and consuls perform useful functions in the host states.  They provide permanent presence in host States, pursue friendly relations between their States and the host States, and promote the various interests of their States in the host states.