Alexandrian Businessman-Missionary (Church of the East), 6th Century: One of the world's first world geographers. His name includes a title that refers to sailing to India. Was an Alexandrian merchant and later hermit monk. As a 6th-century traveler, he made several voyages to India during the reign of Byzantine Emperor Justinian. Was a pupil of the East Syrian Patriarch Aba I and was himself follower of the Church of the East. Around 550 he wrote the illustrated Christian Topography, a work partly based on his personal experiences as a merchant on the Red Sea and Indian Ocean in the early 6th century. That work contained some of the earliest and most famous world maps. His description of India and Sri Lanka is invaluable to historians. He seems to have personally visited the Kingdom of Axum in modern Ethiopia, as well as Eritrea, India, and Sri Lanka. There had been trade between the Roman Empire and India from the 1st century BC onwards, but his report is one of the few from individuals who had actually made the journey. In 522, he visited the Malabar Coast (South India). For centuries Indian Christian churches have claimed that the Apostle Thomas brought the gospel to India. Thomas' trip would certainly have been possible for a Roman Jew to have made. Communities such as the Cochin Jews and the Bene Israel are known to have existed in India around the 1st century. The earliest text connecting Thomas to India is the Acts of Thomas, written in Edessa perhaps in the 2nd century. Eusebius of Caesarea mentions that his mentor Pantaenus found a Christian community in India in the 2nd century, while references to Thomas' Indian mission appear in the works of 3rd and 4th century writers of the Roman Empire, including Ambrose of Milan, Gregory of Nazianzus, Jerome, and Ephrem the Syrian. Whatever the historicity of the Thomas tradition, the earliest known organized Christian presence in India dates to around the 3rd century, when East Syrian settlers and missionaries from Persia (Church of the East or Nestorian Church) established themselves in Kerala. The Indian St. Thomas Christians trace the further growth of their community to the mission of Thomas of Cana, a Nestorian from the Middle East said to have relocated to Kerala some time between the 4th and 8th century. As the community grew and immigration by East Syrians increased, the connection with the Church of the East, centered in the Persian capital of Seleucia-Ctesiphon, strengthened. From the early 4th century the patriarch of the Church of the East provided India with clergy, holy texts, and ecclesiastical infrastructure. This Alexandrian businessman was the first traveler to mention Syrian Christians in India. His reports gave credence to the ancient claim that the Apostle Thomas established Christianity in India (Kerala and Tamil Nadu) in the 1st century. Around 650 Patriarch Ishoyahb III solidified the Church of the East's jurisdiction over the Saint Thomas Christian community.