Vatican II created possibilities for cooperation heretofore unlikely between Protestants and Catholics.

The Second Vatican Council, or Vatican II, an ecumenical council addressing the Catholic Church’s relationship to the modern world, opened on October 11, 1962 and closed on December 8, 1965. Pope John XXIII, who gave notice of convening the council within months of his election, noted that it was time to open up the windows of the church and let in some fresh air. Among the decisions was to issue Unitatis Redintegratio, the decree on ecumenism, promulgated in November 21, 1964, which laid out the ways and means for all Catholics to respond to a “desire for the restoration of unity among all the followers of Christ.”