After several preliminary meetings between representatives of the Vatican Secretariat for Christian Unity and of the World Council of Churches, the mandate for the Joint Working Group was presented to and adopted by the Central Committee at its meeting in Nigeria in January 1965. It was thereafter also officially accepted by the authorities of the Roman Catholic Church.

In working out this project, the Roman Catholic side was guided by the Decree on Ecumenism, promulgated at the end of the third session of the Vatican Council; while the representatives of the World Council of Churches based their approach on the main lines of several WCC documents that describe the nature and function of the World Council and on various statements made by the World Council on the contemporary ecumenical situation.

The Joint Working Group was not set up to undertake negotiations. Its work is to be more limited: it is intended to examine possibilities in the field of dialogue and cooperation. Moreover, it has no power to take decisions. Its business is the joint study of problems, and thereafter to report to the comĀ­petent authorities on both sides.

Its task, both spiritual and pastoral, is to be undertaken in a spirit of prayer, and in the conviction that God is guiding His people. The Group is not limited to settling the technical and administrative aspects of collaboration; it is called on to discern the will of God in the contemporary ecumenical situation.