Christological formulations, using Syriac term qnoma (ܩܢܘܡܐ) as designation for dual (divine and human) properties within one prosopon (person) of Christ. Theological estrangement between East Syriac and West Syriac branches was manifested as a prolonged rivalry, that was particularly intensive between the Church of the East and the Maphrianate of the East (Syriac Orthodox Church), with each branch claiming that its doctrines were not heretical while also accusing the other of teaching heresy. Their theological estrangement has persisted through the medieval and early modern periods and into the present era. In 1999, the Coptic Orthodox Church, a sister-church of the Syriac Orthodox Church, blocked admittance of the Assyrian Church of the East to the Middle East Council of Churches, which has among its members the Chaldean Catholic Church, and demanded that it remove from its liturgy the mention of Diodorus of Tarsus, Theodore of Mopsuestia and Nestorius, whom it venerates as "the Greek doctors". East-West liturgical contrast The liturgies of the East and West Syriacs are quite distinct. The East Syriac Rite is noted especially for its eucharistic Qurbana of Addai and Mari, in which the Words of Institution are absent. West Syriacs use the Syro-Antiochian or West Syriac Rite, which belongs to the family of liturgies known as the Antiochene Rite. The Syriac Orthodox Church adds to the Trisagion ("Holy God, Holy Mighty, Holy Immortal, have mercy on us") the phrase "who were crucified for us". The Church of the East interpreted this as heretical. Patriarch Timothy I of the Church of the East declared: "And also in all the countries of Babylon, of Persia, and of Assyria, and in all the countries of the sunrise, that is to say, among the Indians, the Chinese, the Tibetans, the Turks, and in all the provinces under the jurisdiction of this Patriarchal See, there is no addition of Crucifixus es pro nobis". Among the Saint Thomas Christians of India, the East Syriac Rite was the one originally used, but those who in the 17th century accepted union with the Syriac Orthodox Church adopted the rite of that church. Further divisions A schism in 1552 in the Church of the East gave rise to a separate patriarchate, which at first entered into union with the Catholic Church but later formed the nucleus of the present-day Assyrian Church of the East and Ancient Church of the East, while at the end of the