Mar Eshai Shimun XXIII

Mar Eshai Shimun XXIII (born 28 February 1908, Konak, İzmir, Turkey - assassinated 6 November 1975, San Jose, California, United States), sometimes known as Mar Shimun XXI Ishaya, was Catholicos Patriarch of the Assyrian Church of the East from 1920 until his assassination on 6 November 1975. (The difference in regnal numbers depends on which members of the Shimun family one counts as Patriarchs; Mar Eshai himself used the regnal number XXIII.)

Born into the patriarchal family in Qudshanis, in the village of Van, in Ottoman Turkey in 1908, at the age of 11 Mar Eshai was chosen as patriarch after the death of his uncle during the Assyrian Genocide. He was educated in England at Westcott House, University of Cambridge. He was the translator or author of several books on the theology and history of the Church of the East. The uncertainties caused in 1933 by the independence of Iraq from colonial rule forced the patriarch's relocation to Cyprus and then, in 1940, to Chicago. Mar Eshai became an American citizen in about 1949 and settled in the San Francisco area in 1954.

A dispute over hereditary succession and church calendars caused the metropolitan of the Church of the East in India (known there as the Chaldean Syrian Church) to break away in 1964. The rift was healed only in 1995, thanks to Mar Dinkha IV, though a small group (the Ancient Church of the East) remains separated from the main body of the Church of the East.

The patriarch sought to resign for health reasons in the late 1960s, but was persuaded to remain in office. Many within the church believed that the patriarch should take a more active role, as he had before 1933, in pushing for a homeland for the Assyrian people. Shortly thereafter the patriarch became convinced that nothing in the canon law of the Church of the East prohibited the patriarch from marrying. He therefore married in August 1973.

Following this action, church leaders called for a council to decide the future of the patriarchate. The council was scheduled for 19 November 1975, but was rescheduled for 5 January 1976. In the meantime, on 6 November 1975, the patriarch was shot and killed at the door of his home in San Jose, California, by David Malek Ismail. According to records of Ismail's trial, Ismail indicated that he was upset over the patriarch's marriage; however, the records also suggest links between Ismail and persons who may have been angry at the patriarch's refusal to push for an Assyrian homeland. When the church council finally met in London on 17 October 1976, it elected Mar Dinkha IV (who had been bishop of Tehran) as patriarch.