East Syrian Rite

The East Syrian Rite is a Christian liturgyalso called Assyrian Rite or the Persian Rite, originated in Edessa, Mesopotamia. It was used historically in the Church of the East, and remains in use in churches descended from it; namely the Assyrian Church of the East (Including the Chaldean Syrian Church of India), the Ancient Church of the East, the Chaldean Catholic Church, and the Syro-Malabar Catholic Church. The latter two churches are Eastern Catholic Churches in full communion with the Holy See.

The Syrian and Mesopotamian (Iraqi) Catholics are now commonly called Chaldeans (or Assyro-Chaldeans). The term Chaldean, which in Syriac generally meant magician or astrologer, denoted in Latin and other European languages (Greater) Syrian nationality, and the Syriac or Aramaic language. For Aramaic, it especially refers to that form which is found in certain chapters of Daniel. This usage continued until 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, which they call "Syrians". It is also used to distinguish from the Assyrian Church of the East, some of whom call themselves Assyrians or Surayi, and even "Christians" only, though they do not repudiate the theological name "Nestorian". Modern members of the Assyrian Church of the East and the Ancient Church of the East distinguish themselves from the rest of Christendom as the "Church of the East" or "Easterns" as opposed to "Westerns", by which they denote Orthodox, Syriac Orthodox or Syrians.

...
Wikipedia