The journal was established by Anton van den Boogaard, a Dutch businessman who served as treasurer and President of the Concilium Foundation,[1] Paul Brand, Yves Congar, Hans Küng, Johann Baptist Metz, Karl Rahner, Henri de Lubac, Hans Urs von Balthasar, and Edward Schillebeeckx.

Balthasar and de Lubac later resigned and founded Communio, which became the rival journal of Concilium.

It is published in six languages: Croatian, English, German, Italian, Portuguese, and Spanish.

Concilium aims at promoting theological discussion in the "spirit of Vatican II" from which it was born.

It is a Catholic journal, but is open to other Christian theological traditions and non-Christian faiths.