The beginnings of IMCS can be traced back past our “official” founding in 1921 in Fribourg, Switzerland, to the late 19th Century with the International Union of Catholic Students. In 1921, a diverse group of existing national federations of Catholic university students from Europe, Argentina, Java (Indonesia), and the United States, founded IMCS with the name of Pax Romana, to express their desire to build peace and solidarity in a world torn apart by war. Since then the identity of IMCS at the international, regional, national, and local levels has changed and grown to meet the challenges of the world and the local context in which they are active. The identity, name and structure of each national movement within IMCS also often differs from county to country.
Although, IMCS was founded by a majority of European student movements, IMCS quickly began to grow into the other regions by helping organize new national federations and incorporate preexisting ones. In the 1930s and 1940s, IMCS grew quickly in the Americas and Australia. The 1950s, saw the rapid growth of IMCS in Asia. In the 1960s, IMCS began to have a significant presence in Africa. Today, IMCS in continuing to grow especially in Africa, Asia Pacific, Eastern Europe, and the Middle East.
This ability to adapt to “read the signs of the time” and to address the different realities in which IMCS exists, is a main reason why IMCS has been able to last over 80 continuous years. At all times, IMCS has sought to address many significant challenges facing the world. World War I and II gave our movement the role of a peace movement. The challenges and changes of the Post World War II era with the Cold War and the Second Vatican Council focused our identity on issues of social justice, human rights, refugees, liberation theology, ecumenical dialogue and more attention to the grassroots level. In today’s globalized world IMCS faces new challenges with fundamentalist excesses and intolerance, war and new conflicts, excessive capitalism, excessive individualism, increasing marginalisation, the challenges of HIV/AIDS, and a growing divide between the rich and the poor.
In the 1940s our movement inspired the founding of ICMICA-Pax Romana and for the next thirty years the two branches of Pax Romana would share offices in Fribourg. In 1946, the International young Catholic Students (IYCS) was formed in a meeting held simultaneously with the Congress of IMCS-Pax Romana. Since then, with many ups and downs, our two movements have developed a strong relationship with some IMCS movements adopting IYCS methodologies (Review of Life, See, Judge Act, etc) and with the creation of joint regional co-ordinations in Europe, Latin America and the Middle East. This relationship also led IMCS-Pax Romana in 1977 to move from sharing offices with ICMICA-Pax Romana in Fribourg to sharing offices with IYCS in Paris.
 Second Vatican Council Gaudium et Spes, 1965, 4
Amidst all these changes however we have maintained a core identity that is still present in our movement today as we try to address the new challenges facing us. The document “Toward a Re-Definition of the Movement” from the 1975 IMCS Interfederal Assembly pointed to three main realities in our core identity which are still valid today.
- Student movement
The constituency of IMCS has been made up of national movements of Catholic university or post–secondary students. At the heart of the constituency have always been however, the students themselves. As a student movement, IMCS is concerned with the student and the role of education as a whole. This concern is not limited to the classroom but includes all dimensions of student life (including social, spiritual, physical and familial). This compels us to work with other student movements and organizations dealing with education at the local and international levels (including student organizations of other faiths and denominations and other civil society organizations). In this work we are actively involved in the work of UNESCO. As a student movement, we are not only concerned with student issues but seek to raise awareness and action among students to broader issues of social justice. In this reality we recognize that we are not apart from society and are not just the future of society but we are an active part of it today with a special responsibility as students to question and analyze the problems of society.
- Church Movement
A second element of the identity of IMCS is its role as a Church Movement at the local, national and international level. As the IMCS International Team pointed out in 1987 with the occasion of the Synod on the Laity, IMCS is not only a Church Movement but is ”the Church in movement.” As an international lay movement IMCS is recognized by the Pontifical Council for the Laity and by the Secretariat of State of the Holy See (Vatican). As an International Catholic Organization, IMCS is able to have a strong voice for its members within the global Church. At the national level, IMCS movements and federations are recognized by their local national bishops’ conference. At the regional level, most of the IMCS regions have developed strong relationships with the regional Church bodies. The 1971 reflection on IMCS’s identity clearly stated IMCS’s dual mission as a Church movement: “We also want the Church to be present in the student milieu, and the student milieu within the Church.”
Long before the ecumenical push of the Second Vatican Council, IMCS has sought to build relationships and to include in its programs students of other faith traditions. Often IMCS has held joint meetings with the World Student Christian Federation (WSCF) and at one point in the 1960s held joint regional offices with WSCF for North America. In addition to promoting ecumenical dialogue, IMCS believes that the promotion of inter-religious dialogue among students and student groups is a central part of its mission.
- International Movement
Since its very beginning IMCS has taken its international identity seriously, helping its members to develop a global perspective of their reality, and to enable them to have a voice and impact in the international arena. The international dimension of our movement offers us a chance to promote solidarity, to share our vision and to undertake common actions. IMCS believes that it is through this dialogue between cultures that we understand the universality of the message of the Gospel and we can help build peace in the world.
Based in the student and Catholic perspective, IMCS has used its international identity to speak out on behalf of its members and in solidarity with the oppressed in many important forums including the League of Nations and then with the United Nations and UNESCO. Under the common name of Pax Romana, IMCS and ICMICA advocate in these forums as a non governmental organization in consultative status with the UN ECOSOC. Today IMCS is one of the leading youth NGOs working with the UN, and has played an active role in many of the major UN Conferences in the past 10 years.
At the moment IMCS – Pax Romana is actively present in about 80 countries throughout the world. These national groups make up the core of the IMCS membership. Each national group has a different name, structure, and program. The federated structure of IMCS allows each national movement, federation, association, etc to have autonomy to maintain and develop its own identity to meet the local realities they face, and together at the regional and international levels to face common global challenges and build a common vision.
The diverse regional structures of IMCS which have developed in recent decades provide an invaluable space for the national movements to connect with one another at the regional levels and to reflect and take action on common issues. At the same time, they promote the global reality and identity of IMCS as a whole.
- Educational Movement
IMCS Pax Romana accompanies the progressive growth process of involvement and experience of faith of each member of the movement, in a comprehensive way and in relation with the whole life, in perspective of continuity which does not stop at the end of studies but goes on even more in professional life.
 IMCS “Our Mission in the University,” 1987, 11.
 IMCS Reflection on Identity 1971.