Understanding Chalcedon before the Council of 451 AD

Exploring Ancient Chalcedon in Modern Kadıköy

• Ancient Chalcedon in Modern Kadıköy
• Reading the Ruins of Ancient Chalcedon
• Searching for St. Euphemia Basilica in Chalcedon
• Understanding Chalcedon before the Council of 451 AD

The gospel reached Chalcedon long before the Council of Chalcedon (AD 451). Ancient Bithynia, mentioned in the Bible (Acts 16:7 and 1 Peter 1:1), became a key region for the spread of Christianity. By the time the council met, Christians had flourished there for centuries.

1st Century: The Gospel Reaches Chalcedon

The New Testament does not mention Chalcedon, but the city’s strategic position on the Bosporus, opposite Byzantium (later Constantinople), made it an early stop for the gospel as it spread from Jerusalem along Roman roads and sea routes through Asia Minor.

For Chalcedon, the seaport and the travel routes from the East brought the gospel to this region. Churches in Ephesus, Nicomedia, Nicaea, and other major Roman highway cities likely introduced Christianity to Chalcedon in the late first century. Merchants, sailors, pastors, and apostolic letters connected these churches, helping to establish Christianity throughout Bithynia.

2nd Century: A Growing Church Under Persecution

By the early second century, Christianity had spread widely through Bithynia. Around AD 111–113, Governor Pliny the Younger wrote to Emperor Trajan about the growing number of Christians appearing before him. Roman authorities punished Christians, especially when they refused to participate in traditional Roman worship. The high volume of cases led Pliny to ask Trajan for guidance, as the situation had become rampant.

He reported that Christianity had spread through cities (such as Chalcedon), villages, and rural areas, and that this growth had disrupted traditional pagan worship. Pliny discovered that Christians met before dawn to sing hymns to Christ and later gathered for a communal meal. Although Pliny did not mention Chalcedon by name, the city was part of Bithynia and therefore fell within the scope of this Christian expansion.^[1]https://sourcebooks.web.fordham.edu/source/pliny1.asp

This account reveals public Christianity in the early second century in the eastern regions of modern Istanbul.

3rd-4th Century: From Hidden Congregation to Established Church

In the third century, Christians in Chalcedon organized their community and appointed a bishop. The records are sparse but tradition gives semblance in honor of those who were martyred during the early years of the 4th century before church freedom became normal.

Chalcedon became known for the martyr Euphemia, who suffered during Diocletian’s persecution around AD 303. Her story shaped the city’s Christian identity and influenced the council’s location. Christian tradition places her death during the Great Persecution under Diocletian and associates her with a group of Christians who refused to participate in pagan sacrifice. “The Chalcedon governor Priscus circulated an order to all the inhabitants of Chalcedon and its surroundings to appear at a pagan festival to worship and offer sacrifice to an idol of Ares, threatening grave torments for anyone who failed to appear. During this impious festival, 49 Christians were hidden in one house, where they secretly attended services to the True God.”^[2]https://www.antiochpatriarchate.org/en/page/saint-euphemia-the-great-martyr/755 Later, her martyr shrine became an important Christian center in Chalcedon. The archeology dig has produced sacred bone remains that could have associated with this martyrium center.^[3]https://www.turkiyetoday.com/culture/uncovering-secrets-of-ancient-chalcedon-beneath-modern-kadikoy-141292?s=2

Chalcedon located on the west end of the Silk Road, which meant that travelers came by land as well as by the nearby port. Influences from Nicaea and also points south would often reach the city.

Others who seemingly passed through died there. St. Victor and Sosthenes were soldiers ordered to execute Lady Euphemia. When they saw God’s hand in her life, they became believers only to be speedily martyred. Also, St. Sabel the Persian and his companions were killed for their faith in Christ. The Silk Road passed through the area on the way to Scutari (Üsküdar) tradition states they were officials from Persia. So we see that their deaths preserves an important memory of Christianity crossing political and cultural boundaries between Persia and the Roman world.

Constantine and Helena’s Influence

Constantine the Great created an environment where the church could thrive. After the Edict of Milan (313 AD), Constantine supported church construction across the empire and made Constantinople (330 AD) the hub of politics and religion. After the Council of Nicaea (325 AD), the region’s churches gained influence. His mother, Helena, born in nearby Altınova, established worship sites associated with Christianity’s origins during her visits to the Holy Land.

In light of their influence, the believers built churches like the Church of Bassa near to this ancient port and the St. Euphemia Basilica that most likely sat upon the hillside above the ruins.^[4]https://www.newadvent.org/cathen/03554a.htm

Reasons for Chalcedon to Host the Council

Here are some practical and symbilic reasons Chalcedon council in 451 AD.:

1. Close to Constantinople: The city was just across the Bosporus, making travel easy for bishops and officials, and avoiding the politics of meeting in the capital itself.

2. Sizable Location: The Basilica of St. Euphemia was large and could hold over 500 bishops. This location offered a very acceptable setting for the council.

3. Christian History: The established church respected Chalcedon’s stand for the faith and its community.

4. Honoring a Martyr: The council met near the shrine of St. Euphemia, a local martyr, as a reminder of those who stayed faithful under persecution. A key subject of the council was to defend the faith and doctrine of the church.

Long before AD 451, the gospel reached Chalcedon through first-century church efforts and Roman networks. In the following centuries, Christians endured persecution, organized a bishopric, and became known through Euphemia’s martyrdom. Constantine did not establish the church, but by legalizing Christianity and founding nearby Constantinople as capital, he elevated the region’s importance. These developments made Chalcedon an ideal location for one of history’s most influential councils.

Possible Early Bishops of Chalcedon

Based on traditions and church history we can form a sequence of Bishops before AD 451:^[5]See Michel Le Quien, Oriens Christianus in quatuor patriarchatus digestus, vol. 1 (Paris, 1740), 599; Sophrone Pétridès, “Chalcedon,” The Catholic Encyclopedia, vol. 3 (New York: Robert … Continue reading

1. Adelphius (traditional, uncertain)
2. Maris (attested at Nicaea, AD 325)
3. Heraclian (traditional)
4. Cyriacus (traditional)
5. Eulalius (late 4th century)
6. Cosmas (early 5th century)
7. Eunomius (bishop immediately before the Council of Chalcedon)

Thus, despite Chalcedon’s later fame as the site of the great council of AD 451, the names of its early bishops are surprisingly few. The city’s lasting significance rests less on a continuous record of famous bishops than on its longstanding Christian community and its role as the meeting place where bishops from across the Christian world gathered to define orthodox Christology.

Historic records in stone or inscriptions of Chalcedon’s earliest bishops have largely disappeared, but their names and voices have not. Maris appears in the record of Nicaea, while Heraclian was remembered for a twenty-book defense of the Christian faith against Manichaeism.^[6]A dualism that most likely was influenced by Zoroastrian thought upon Christianity. Their surviving historical footprint shows that Chalcedon was not simply a convenient location chosen for the council in 451, but a location that already possessed a long Christian history.

Chalcedon Ideas Today

The story of Chalcedon is more than the history of an ancient city and a theological controversy. It shows how seriously the early church took the identity of Jesus. At Nicaea, the church defended the truth that the Son is of the same substance with the Father. At Chalcedon, the church defended the truth that Jesus Christ is fully God and fully human, one person with both divine and human natures.

These debates centered on an important question: What does it mean for God to be one? The early church did not debate these matters simply to settle theological disagreements. The church believed that the answer shaped how Christians understood God, Jesus, salvation, and their relationship with God.

That question remains important today. When Christians say that God is one, what do we mean? Does God’s oneness simply mean that there is only one God, or does Scripture reveal a deeper kind of oneness between the Father and the Son? And if God’s own oneness shapes our understanding of him, what does it tell us about the oneness God desires among his people?

I explore these questions in The Absurdity of God’s Oneness. The gospel spread across the ancient world because Christians proclaimed the God they had come to know through Jesus Christ. The debates at Nicaea and Chalcedon show why the early church defended that message so carefully. What Christians believed about the oneness of God affected what they believed about Jesus himself.

Chalcedon therefore connects the history of the gospel with a question that still deserves our attention: If God is one, what does his oneness actually mean? That question stands at the heart of The Absurdity of God’s Oneness.