The East Syrian Rite is a Christian liturgy, also known as the Thomasine Rite, Assyrian-Chaldean Rite, Assyrian Rite and 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, 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.