Second Vatican Council
The Second Ecumenical Council of the Vatican, commonly known as the or , addressed relations between the Catholic Church and the modern world. The council, through the Holy See, was formally opened under the pontificate of Pope John XXIII on 11 October 1962 and was closed under Pope Paul VI on the Solemnity of the Immaculate Conception on 8 December 1965.
Unitatis redintegratio
Unitatis redintegratio (Latin for "Restoration of unity") is the Second Vatican Council's decree on ecumenism. It was passed by a vote of 2,137 to 11 of the bishops assembled, and was promulgated by Pope Paul VI on 21 November 1964. Its title is taken from the opening words of the Latin text. The opening of the document's English translation is: "The restoration of unity among all Christians is one of the principal concerns of the Second Vatican Council."