The Second Vatican Council (also known as Vatican II) addressed relations between the Roman Catholic Church and the modern world. It was the twenty-first Ecumenical Council of the Catholic Church and the second to be held at St. Peter's Basilica in the Vatican. It opened under Pope John XXIII on 11 October 1962 and closed under Pope Paul VI on 8 December 1965. Of those who took part in the council's opening session, four have become pontiffs to date: Cardinal Giovanni Battista Montini, who on succeeding Pope John XXIII took the name of Paul VI; Bishop Albino Luciani, the future Pope John Paul I; Bishop Karol Wojtyła, who became Pope John Paul II; and Father Joseph Ratzinger, present as a theological consultant, who became Pope Benedict XVI.

Throughout the 1950s, theological and biblical studies of the Catholic Church had begun to sway away from the neo-scholasticism and biblical literalism that the reaction to Catholic modernism had enforced since the First Vatican Council.^{[citation needed]} This shift could be seen in theologians such as Karl Rahner, S.J., Michael Herbert, and John Courtney Murray, SJ who looked to integrate modern human experience with church principles based on Jesus Christ, as well as others such as Yves Congar, Joseph Ratzinger and Henri de Lubac who looked to an accurate understanding of scripture and the early Church Fathers as a source of renewal (or ressourcement).

The First Vatican Council took place in 1869 - 1870 and was the 20th of ecumenical councils recognized by Roman Catholicism.

The Second Vatican Council took place in the 1962 - 1965 and was the 21st.