In response to King Abgar’s letter to Jesus, church tradition tells us that Jesus directed the apostle
Thomas to send Thaddeus (Addai in Syriac)—one of the seventy apostles (Luke 10:1)—to Edessa (modern Urfa). Through Addai’s ministry, King Abgar was healed and the city of Edessa became Christian. It is believed that the apostle Thomas also engaged in an eastern mission journey beyond the borders of the Roman empire, reaching India by 52, about the time that the apostle Paul had finished his western second missionary journey. The Acts of Thomas was written in Edessa around 200. It is one of the most important documents in early church history because it is the oldest narrative that describes the church going east beyond the borders of the Roman empire. The last chapters of the Acts of Thomas have Thomas reaching and dying in India. It is said that his body was brought to Edessa by an Indian merchant.