1962-1965: Second Vatican Council

During the Second Vatican Council, IMCS, and IMCS friends played important roles. Pax Romana ICMICA Secretary General Ramon Sugranyes de Franch was chosen as one of the 12 Lay Auditors of the Council. Australian Rosemary Goldie who was a former member of the international secretariat (and founder of IMCS in Australia), was very active as one of the few lay women to be involved in the Council and she would later become the first lay woman to work in the Roman curia. Former IMCS chaplain, John Courtney Murray, SJ, assisted by former IMCS president Ed Kirchner, played a key role in the writing of the Declaration of Religious Freedom.

Before the Council, IMCS and IMCS federations were already "reading the signs of the times" and responding to them. The documents of the Council only deepened IMCS' commitment to social justice, living the "Gospel in the modern world," inter-religious and ecumenical dialogue, and the important role of the laity in the Church.

In 1963, during the Council, the Church elected Giovanni Battista Montini as Pope Paul VI. This was a great milestone for IMCS-Pax Romana, as Montini had served as national chaplain for FUCI (IMCS Italy) in the 1920s. As chaplain, Montini had participated in several IMCS Pax Romana activities and later as Secretary of State, Montini kept close relations with Pax Romana.