This year the church worldwide observes the 1,700th anniversary of the First Council of Nicaea. Held in the Roman city of Nicaea in present-day northwestern Turkey, between May and July 325, this gathering of bishops and leaders of the church was the first to be identified as “ecumenical,” the definition of which has evolved in the last 1,700 years. A great deal, good and regrettable, has occurred in the life of the church in those 17 centuries.

The council coincided with profound changes in the Greco-Roman world in general and in the Christian world in particular. At the end of the third century and beginning of the fourth, the Roman emperor Diocletian unleashed one of the most brutal persecutions of Christians in the history of the empire — although the thoroughness of the brutality varied from place to place. In addition to wiping out any challenge to his authority, and to further consolidate his power and secure the borders of his sprawling empire, which extended from Persia to Britain, he restructured the empire into four self-governing units led by two senior emperors, known as “augusti,” and two junior colleagues understood to be their designated successors, called “caesares.”

In 306, a year after Diocletian’s abdication, Constantine was proclaimed emperor by his army at Eboracum, present-day York, England. He eventually emerged victorious in the civil wars against his peers, Maxentius and Licinius, to become the sole ruler of the Roman Empire by 324.

During this period, Constantine attributed his victories to a special relationship he felt with the God of the Christians, “in whose sign he conquered,” including his victory over Maxentius at the Milvian Bridge on 28 October 312.

Thus, in a period of roughly 20 years, Christianity emerged as the favored religion of the emperor and, hence, the empire. As with Diocletian, consolidating power and securing the borders ranked high among Constantine’s priorities. The political and the religious spheres were not separate then, and division and chaos, whether political or religious, were to be avoided and overcome at all costs.

There were several challenges disrupting the unity of Christians in his realm, however. The most significant involved the priest Arius, whose teachings denied the full divinity of Christ. This was not the first time Constantine had to deal with inner-Christian issues. In 314, he had convoked the Synod of Arles to address the controversy of the Donatists, a heretical sect in North Africa. Ultimately, it was Constantine who, without consulting the bishop of Rome, decided on and convoked the first council to be held in Nicaea.

The fact of the not-yet-baptized Constantine convoking and presiding over the first ecumenical council has been a source of some cognitive dissonance philosophically and theologically between the Christian East and the Christian West. This dissonance is perhaps most evident in the iconography of the council. In the Christian East, where Constantine is revered as a saint along with his mother, Helen, the emperor is depicted in the center of the icon as presiding over the council. Seated on either side of him without precedence in synodal fashion are the bishops, depicted in Byzantine vestments, each holding the Gospel. A vanquished Arius lies at the feet of the council fathers.

In the art of the Christian West, the delegate of the pope is flanked by two cardinals and presides over the council. Bishops in Latin-rite vestments listen and confer with each other as the heresies of Arius, who stands as if on trial, are read aloud. Constantine usually is depicted at the periphery of the image, being informed of the proceedings rather than guiding them.

The Western portrayal is clearly anachronistic, applying a much later Western understanding of ecumenical councils.

It is important to understand the development of the ecumenical councils in a constantly dividing Christian world. Almost every council, including Vatican II (1962-1965), has produced dissidents, some of whom became schismatic and excluded — oftentimes by self-exclusion — from communion with the Church of Rome.

While not directly connected with an ecumenical council, the mutual excommunication of the pope and the ecumenical patriarch in 1054, known as the Great Schism, which began the formal drifting apart of the Catholic West and the Orthodox East, has led the Orthodox to reject all Catholic general councils after 1054 as non-ecumenical because of the non-participation of the Orthodox. Both technically and theologically, this is a crucial point.

The word “ecumenical” originally referred to that which involved all Christians from the “inhabited world” (“oikumene” in Greek), which were in communion or agreement in the faith. Tragically, each “ecumenical” council made the meaning of the word “ecumenical” more restrictive and less inclusive.

In the 19th century, Protestant missionary groups began to realize that the almost endemic divisions of Christianity made the message of the Gospel less credible. The division among Christians was not a situation to be endured, but a sin to be overcome. Slowly, a movement to restore unity among Christians began.

The two great and horrible wars of the 20th century, waged primarily, although not exclusively, by Christians, gave a terrifying impetus to the emerging movement. Among other initiatives, the World Council of Churches was founded in 1948. With the 1964 publication of Vatican II’s Decree on Ecumenism, “Unitatis redintegratio,” the Catholic Church committed to the search for Christian unity. But an interesting phenomenon occurred. 

With Christians committing to search for unity, the meaning of the word “ecumenical” took on a new meaning, opposite to its original use. If for centuries an ecumenical meeting was among believers in communion with each other, now it came to mean a meeting among believers who do not share communion yet hope to restore it. The “ecumenical” Council of Nicaea was not “ecumenical” in the same way as ecumenical would be understood today for 21st-century Christians.

The goal of Nicaea — unity in faith among Christians — remains, but the methodology has changed almost 180 degrees and, if we are honest, continues to evolve. Pope Francis and Ecumenical Patriarch Bartholomew of Constantinople have contributed greatly to that evolution.

One hears of an ecumenism of friendship. It is obvious the two hold each other in esteem. Neither one minimalizes the theological differences that divide them. Neither one denies the importance of ongoing theological dialogue. However, both men realize people can differ, even significantly, and still have a profound friendship and affection for each other. Francis and Bartholomew show us we do not have to achieve “perfect unity” — perhaps an eschatological goal anyway — before we can love each other and work together to achieve the many things we hold dear and in common.

An example of this newer form of ecumenical encounter is the annual visits of the two church leaders. On 29 June, the feast of Sts. Peter and Paul, patrons of Rome, the ecumenical patriarch sends a delegation to attend the celebrations presided over by the bishop of Rome. On 30 November, the feast of St. Andrew, patron of Byzantium (re-founded by Constantine as New Rome, but commonly called Constantinople until the adoption of its Turkish name, Istanbul, in 1930), the bishop of Rome sends a special envoy to celebrate the patronal feast of the ecumenical patriarchate, now located in an unassuming complex in Turkey’s bustling cultural, economic and historic capital.

By any measure, 1,700 years is a long time. The weight of history is heavy and there is a temptation to let it dominate the observance. Nicaea is a historical event to be sure. However, as with many religious observances, it is an event that is not merely archival. Nicaea is about the past, but not just the past, as the shift in the Christian understanding of the meaning of “ecumenical” demonstrates. It might point to a new way and provide Christians today with a new impulse and tools for the next stage in the road to Christian unity.

The pope’s message for the visit to Constantinople in 2024 was special in that he suggested the two churches observe and celebrate the anniversary. He wrote: “The now imminent 1,700th anniversary of the first ecumenical Council of Nicaea will be another opportunity to bear witness to the growing communion that already exists among all who are baptized in the name of the Father and of the Son and of the Holy Spirit.”

This is not merely a symbolic gesture, although it is a powerful symbol. It is a practical action showing not only a true bond of affection, but a concretization of the unity that already exists between the two churches — something to celebrate indeed.

Read this article in our digital print format here.