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.
Catholic Church in the 20th century
A major event of the Second Vatican Council, known as Vatican II, was the issuance by Pope Paul VI and Orthodox Patriarch Athenagoras of a joint expression of regret for many of the past actions that had led up to the Great Schism between the Western and Eastern churches, expressed as the Catholic-Orthodox Joint declaration of 1965. At the same time, they lifted the mutual excommunications dating from the 11th century.