Rebuilding Christian unity has been one of the main purposes of the 2nd Vatican Council. This document has been the official adhesion of the Catholic Church to the ecumenical movement. The accomplishment of Church’s unity is a commitment of the whole Church and not a private initiative of one person. After it speaks about ecumenism and the relations between the Catholic Church and the separated brothers, the Council wishes to offer to all the members of the Catholic Church all the help, the ways and the means to re-establish unity. The practical methods which this document offers are the prayer and the direct dialogue with the other Christians. The approval of this document has lead to the apparition of the Secretariat for the Unity of Christians and to elaboration of some documents that refer to the remaking of the Church’s unity.