The Law of State succession results from States’ temporal validity as subjects of International Law. The Law of State succession studies the effects of State extinction. The doctrine has two elements: the territorial element and the so called phenomenon of succession. There are five cases to which International Law attributes the effects  of a legal succession: the transference of a part of a territory (cession), decolonization, unification, separation (secession) and dissolution. Treaty law regulates State succession in respect of treaties (Vienna, 1978) and in respect of State property, archives and debts (Vienna, 1983). The Treaty of 1983 is not in force yet, probably because of the special treatment conferred to newly independent States (decolonization). Other than the aspects regulated by the Treaties of 1978 and 1983, succession of States has effects on the nationality and the legal status of the inhabitants of the territories affected by a succession. Succession of States also affects the legal system of the predecessor State, which can be tolerated or modified by the successor State.