The origin of the church in Turkey goes back to the events immediately following the crucifixion and resurrection of Jesus Christ in Judea. On the Day of Pentecost Jews from Cappadocia, Pontus, Asia, Phrygia, and Pamphylia were gathered in Jerusalem (Acts 2:9-10). Many of these became eyewitnesses to the outpouring of the Holy Spirit and Peter's subsequent sermon. Some were undoubtedly among the three thousand who believed on Jesus that day (Acts 2:41).
Returning home, these were the first Christians in Anatolia. One of the most interesting accounts recorded by the early church father Eusebius in his Church History (1.13) is a letter of Abgar V, king of Edessa. Abgar, dying of disease, wrote a letter, requesting Jesus to heal him. In his reply Jesus stated that he could not come but that a disciple would be sent later. After Pentecost Thaddeus was sent by the apostles. When he prayed for Abgar, the king was instantly healed. Abgar and his subjects believed in Jesus, and the kingdom converted to Christianity. Syriac Christianity, which persists in the region of Mardin, traces its historical origins to this tradition.
Although Jesus had commanded the early believers to preach the gospel outside of Jerusalem "to the ends of the earth" (Acts 1:8), this did not happen until the martyrdom of Stephen. Jews from Cilicia and Asia found a willing accomplice to this murder in Saul (Acts 6:9ff.; 7:58-8:1). Although born a citizen of Tarsus, Saul had been brought to Jerusalem as a youth to receive formal training in Judaism (Acts 21:39; 22:3). On the road to Damascus Saul was dramatically converted, and after a time in Arabia and Jerusalem he returned to Tarsus (Acts 9:30; Gal.1:21.
In the meantime those scattered by Stephen's death traveled as far north as Antioch, preaching first to Jews and then to Gentiles. A church quickly formed with many believing in the Lord (Acts 11:19-24). Barnabas brought Saul from Tarsus to assist in discipling these new believers, and at Antioch these believers were first called Christians (Acts 11:25-26).