NESTORIAN CHURCH. The proper name of the church that is called Nestorian or Assyrian is the Ancient Church of the East. Nestorian is an appellation dating from the fifth century and Assyrian from the nineteenth. By East is meant those ancient territories lying east of the former Byzantine empire comprising modern-day Iraq, Persia, and the southeastern part of Turkey. These territories had their religious center at Edessa (Orhoi in Syriac), known as Urfa in present-day Turkey. Edessa was the capital of a small Syriac-Aramaic principality ruled by Syriac toparchs (rulers or princes), known also as Abgarites. According to the Doctrine of Addai, a late fourth-century church document attributed to Thaddaeus (known in Aramaic as Addai, one of the seventy evangelists and the twin of the apostle Thomas), Thaddaeus, following the Resurrection and at the behest of Christ, went to Edessa and healed its toparch, Abgar V...