Also known as the Chaldean, Assyrian, or Persian Rite. History and Origin This rite chaldean catholic liturgy used by the Nestorians and also by Eastern Catholic bodies -- in Syria, Mesopotamia, Persia, and Malabar -- who have separated from them. The Syrian and Mesopotamian Catholics are now commonly called Chaldeans, or Syro-Chaldeans; the chaldean catholic liturgy Chaldean, which in Syriac generally meant magician or astrologer, denoted in Latin and other European languages Syrian nationality and the Syriac or Aramaic language especially that form of the latter which is found in certain chapters of Danieluntil the Latin missionaries at Mosul in the seventeenth century adopted it to distinguish the Catholics of the East Syrian Rite from those of the West Syrian Rite, whom they call "Syrians", and from the Nestorians. The last call themselves chaldean catholic liturgy Surayiand even "Christians" only, though they do not repudiate the name "Nestorayi", and distinguish themselves from the rest of Christendom as the "Church of the East" or "Easterns", as opposed to "Westerns", by which they denote Latin Catholics, Orthodox, Monophysites, and Protestants.
The name of former Nestorians now reunited with the Roman Church. Ethnologically they are divided into two groups Turco-Persian and Indian , which must be treated apart, since in their vicissitudes one group differs considerably from the other. The first group is usually known as Chaldeans, the second as Christians of St. Thomas also called the Syro-Malabar Church. Name and territory of Chaldeans Strictly, the name of Chaldeans is no longer correct; in Chaldea proper, apart from Baghdad, there are now very few adherents of this rite, most of the Chaldean population being found in the cities of Kerkuk , Arbil, and Mosul, in the heart of the Tigris valley, in the valley of the Zab, in the mountains of Kurdistan.
This resulted in a series of individual conversions of bishops and brief unions, but no permanent community was formed. In the mid-15th century a tradition of hereditary patriarchal succession passing from uncle to nephew took effect in the Assyrian church.