key centers of Christianity became the city of Antioch, previous capital of the Hellenistic Seleucid Empire, located in today what is modern Turkey. Antioch was evangelized perhaps by Peter the Apostle, according to the tradition upon which the Antiochene patriarchate still rests its claim for primacy, and certainly by Barnabas and Paul. Its converts were the first to be called Christians. They multiplied rapidly, and by the time of Theodosius (347–395) were reckoned by Chrysostom (347–407), Archbishop of Constantinople, at about 100,000 people. Between 252 and 300, ten assemblies of the church were held at Antioch and it became the seat of one of the original five patriarchates, along with Jerusalem, Alexandria, Constantinople, and Rome. Caucasus Armenia and Georgia were the first nations to adopt Christianity as a state religion, in 301 and 326 respectively. Christianity had been preached in Armenia by two of Jesus' twelve apostles — Thaddaeus and Bartholomew — between 40–60 AD. Because of these two founding apostles, the Armenian Apostolic Church is considered to be the world's oldest national church. In Georgia, Christianity was first preached by the apostles Simon and Andrew in the first century. It became the state religion of Kartli, Iberia (the area of Georgia's capital) in 326. The conversion of Georgia to Christianity is credited to the efforts of Saint Nino of Cappadocia (290–338). Parthian Empire Christianity further spread eastward under the Parthian Empire, which displayed a high tolerance of religious matters. According to tradition, Christian proselytism in Central Asia, starting with Mesopotamia and the Iranian plateau, was put under the responsibility of Saint Thomas the Apostle, and started in the first century AD. Saint Thomas is also credited with the establishment of Christianity in India. The Christians of Mesopotamia and Iran were organized under several bishops, and were present at the First Council of Nicaea in 325 AD. Expansion to Central Asia The spread of Christianity in Central Asia seems to have been facilitated by the great diffusion of Greek in the region (Seleucid Empire, Greco-Bactrian Kingdom, Indo-Greek Kingdom), as well as Aramaic, the language of Jesus Christ. The spread of the Jews in Asia since the deportation from Babylon and the capture of Jerusalem by Titus also seems to have been a contributing factor. The earliest known references to Christian communities in Central Asia is from a writing by Bar Daisan around 196 AD: "Nor do our sisters among the