The Syriac Orthodox Church (ʿIdto Sūryoyto Trīṣath Shubḥo; الكنيسة السريانية الأرثوذكسية, സുറിയാനി ഓർത്തഡോക്സ് സഭ), also known as West Syriac Church or West Syrian Church, officially known as the Syriac Orthodox Patriarchate of Antioch and All the East, and informally as the Jacobite Church, is an Oriental Orthodox church that branched from the Church of Antioch. The bishop of Antioch, known as the patriarch, heads the church and possesses apostolic succession through Saint Peter (Šemʿōn Kēp̄ā), according to sacred tradition. The church upholds Miaphysite doctrine in Christology, and employs the Divine Liturgy of Saint James, associated with James, the brother of Jesus. Classical Syriac is the official and liturgical language of the church.
The church gained its hierarchical distinctiveness in 512, when pro-Chalcedonian patriarch Flavian II of Antioch was deposed by Byzantine emperor Anastasius I Dicorus, and a synod was held at Laodicea in Syria in order to choose his successor, a prominent Miaphysite theologian Severus the Great (d. 538). His later deposition (in 518) was not recognized by the Miaphisite party, and thus a distinctive (autocephalous) miaphysite patriarchate was established, headed by Severus and his successors. During the sixth century, miaphysite hierarchical structure in the region was further straightened by Jacob Baradaeus (d. 578), while the pro-Chalcedonian faction would form to become the Greek Orthodox Church of Antioch (part of the wider Eastern Orthodox Church).
In 1662, the vacant Syriac Patriarchate of Antioch was filled by individuals who aligned themselves with the Catholic Church. Andrew Akijan was elected in that year, and was succeeded by another Catholic in Gregory Peter VI Shahbaddin. The non-Catholic Syriac party elected the rival Abdulmasih I, Shahbaddin's uncle, as a competing patriarch. Upon Shahbaddin's death in 1702, the Catholic line died out for several decades until the Holy Synod in 1782 elected Michael III Jarweh, who again aligned the Syriacs with the pope.