This paper studies the end of the ECSC and the events related to it. Particularly, in the silence of the ECSC Treaty, the paper analyses how these questions have been regulated by the creators of the Community system: the Member States. The paper takes into consideration the relevant set of rules which created a bridge, allowing for the survival of the legal relationships based upon the ECSC Treaty in different fields under a regulatory and administrative umbrella created under EC Treaty, and under the general rules established by it. Finally the paper will juridically qualify the transfer of legal relationships between the ECSC and the EC in the international legal order and in the internal system of each member States, with a particular attention to the Italian one.