The schism, which began in 1364 and lasted until the mid-19th century, was not a battle over theology or dogma. Instead, it was a deeply human clash of egos, regional pride, and geopolitical manipulation that divided the Assyrian nation for generations.
The rift ignited over a bitter personal feud. Patriarch Mor Ignatius Ismail, ruling from the majestic Deyrulzafaran Monastery near Mardin, excommunicated Mor Saba, the influential Archbishop of Salah, based on local rumors. Denied entry to the patriarchal seat, Saba’s furious supporters, consisting of the Assyrian clergy and village elites of Tur Abdin, refused to recognize Ismail's authority. In August 1364, they declared Saba as a rival Patriarch: Ignatius Saba I. Recognizing a golden opportunity to weaken his neighbor, the Kurdish-Muslim Emir of Hasankeyf quickly validated Saba's election, providing the political shield necessary to solidify the split. For the next 480 years, the Assyrian faithful navigated a bifurcated reality: The Patriarchate of Antioch (Mardin) which maintained the historical claim to universal leadership, operating primarily out of Deyrulzafaran, and The Patriarchate of Tur Abdin, with confined jurisdiction to the mountain villages and monasteries of Tur Abdin, operating out of Mor Jakob in Salah and Mor Gabriel.
Remarkably, throughout this entire period, the liturgy, sacraments, and doctrines remained completely identical. An Assyrian villager in Tur Abdin confessed the exact same faith as an Assyrian merchant in Mardin, they simply answered to different spiritual leaders.
Amid widespread political instability in the Middle East, a third faction briefly emerged in Sis (Cilicia), splitting the Syriac Orthodox Church of Antioch into three simultaneous lines.
In 1495 bishops from Tur Abdin travelled to Mardin to sign a reconciliation treaty, temporarily submitting to the main Patriarchate. However, deep-seated regional rivalries caused the schism to flare up again shortly after.
By the early 1800s, the Patriarchate of Tur Abdin began to suffer from internal decay. Multiple local bishops simultaneously claimed the patriarchal title, leading to fractional infighting within the mountain communities. Following the deaths and abdications of the final rival claimants, and facilitated by administrative centralization under the Ottoman Empire, the separate Patriarchate of Tur Abdin was permanently dissolved by 1844.
The split collapsed in the 1840s also due to shifting political realities. As the Ottoman Empire centralized its governance, the local Kurdish and Arab emirs who had protected and exploited the division lost their autonomy. Without external political backing, and crippled by internal rivalries, the line of Tur Abdin dissolved. The last rival hierarchs stepped down or passed away, and the entire Syriac Orthodox Assyrian flock of Tur Abdin peacefully returned to the singular authority of the Syriac Orthodox Church of Antioch. Today, the schism is remembered not as a wound of heresy, but as a testament to the fiercely independent spirit of the Assyrians of the holy mountain.
