Membership is estimated to 170,000 , although some sources say as high as 500,000 The current hierarchy and dioceses is as follows . The patriarchal seat was moved several times throughout history . Up to the 1804 , patriarchs of the senior Eliya line resided in the ancient Rabban Hormizd Monastery , while patriarchs of the junior Shimun line resided in the cathedral church of Mar Shallita , in the village of Qudshanis in the Hakkari mountains of the Ottoman Empire , and continued to do so up to the First World War . After the beginning of conflict in 1915 , the Patriarchs temporarily resided between Urmia and Salmas , and from 1918 the patriarchs resided in Mosul . After the Simele massacre of 1933 , the then Patriarch Shimun XXI Eshai was exiled to Cyprus due to his agitation for independence . In 1940 he was welcomed to the United States where he set up his residence in Chicago , and administrated the United States and Canada as his Patriarchal province . The patriarchate was then moved to Modesto , California in 1954 , and finally to San Francisco in 1958 due to health issues . After the assassination of the Patriarch and the election of Dinkha IV in 1976 , the patriarchate was temporarily located in Tehran , where the new patriarch was living at the time . After the Iran – Iraq War and the Iranian Revolution , the Patriarchate again returned to Chicago , where it remained until 2015 , when it reestablished itself in the Middle East by organizing in Erbil 's Ankawa district in Iraq after the enstatement of Gewargis III . The Diocese of Eastern United States served as the patriarch 's province from 1994 until 2012
Simele massacre
Simele massacre
Assyrian Church of the East