What Do You Know About Ecumenism?

Matthews Otalike, NCC Desk / 7/5/25

The concept of ecumenism has been operational in the Church for centuries. The concept Ecumenism refers to the movement within Christianity aimed at promoting unity among different Christian denominations. The term derives from the Greek word oikumene, meaning "the inhabited world," implying a universal or global Christian community. Ecumenism seeks to overcome historical divisions caused by theological, liturgical, and cultural differences, while respecting the distinct identities of each tradition. Divisions in Christianity, such as the Great Schism (1054) between the Catholic and Orthodox Churches and the Protestant Reformation (16th century), created lasting separations.

The Catholic Church’s commitment to ecumenism was formalized during the Second Vatican Council (1962–1965), particularly through the decree Unitatis Redintegratio (Restoration of Unity, 1964). The Church views ecumenism as a divinely inspired mission rooted in Christ’s prayer for unity: “that they may all be one” (John 17:21).

Theological Foundations

The Catholic Church believes that Christian unity is a divine mandate, reflecting Christ’s intention for his followers to be one (John 17:11, 21–23). Disunity is seen as a scandal that weakens the Church’s witness to the Gospel.

According to Catholic teaching, the Church founded by Christ “subsists in” the Catholic Church (Lumen Gentium, 8), which possesses the fullness of truth and means of salvation. However, other Christian communities share elements of truth and sanctification, making them “separated brethren” rather than adversaries (Unitatis Redintegratio, 3).

Full unity is an ultimate goal, to be fully realized at the end of time, but partial unity can be achieved through human efforts guided by the Holy Spirit.

Therefore, the Catholic Church’s objectives, as outlined in Unitatis Redintegratio and subsequent documents like Ut Unum Sint (1995) by Pope John Paul II, is to achieve visible unity among Christians, ideally through full communion with the Catholic Church, where all share the same faith, sacraments, and apostolic succession under the Pope’s authority. However, the Church recognizes this as a long-term goal and emphasizes intermediate steps.

To foster dialogue that clarifies theological differences (e.g., on justification, the Eucharist, or papal primacy) and identifies shared beliefs. For example, the 1999 Joint Declaration on the Doctrine of Justification with Lutherans resolved key Reformation-era disputes by agreeing to:

- collaborate with other Christians on moral and social issues, such as human rights, peace, and environmental stewardship, demonstrating unity in mission despite doctrinal differences.

- promote “conversion of heart” and prayer for unity, as emphasized in Unitatis Redintegratio (7–8). This includes joint prayer services, such as those during the annual Week of Prayer for Christian Unity.

- seek unity without requiring uniformity, allowing for legitimate diversity in liturgy, spirituality, and governance, as long as essential truths are upheld.

The Catholic Church pursues ecumenism through various means, reflecting her commitment to both theological dialogue and practical cooperation:

- The Dicastery for Promoting Christian Unity (formerly the Pontifical Council) oversees bilateral dialogues with groups like the Anglican Communion, the Lutheran World Federation, and the Orthodox Churches. For instance, the Anglican-Roman Catholic International Commission (ARCIC) has addressed issues like authority and Mary since 1970. Notable achievements include the 1999 Joint Declaration with Lutherans and ongoing discussions with the Orthodox on primacy and synodality and Popes have participated in high-profile ecumenical gestures, such as Pope Francis’s 2016 visit to Lund, Sweden, for the 500th anniversary of the Reformation, co-hosted with Lutherans.

The following list Ecumenical Councils of the Church since year 325 details efforts by the Church to bring about unity in the body of Christ.

Ecumenical ("Universal") Councils of the Church...