Assyrian Church of the East

====Patriarch Shimun XXI Eshai====
{{Main|Shimun XXI Eshai}}
In the aftermath of World War I, the British-educated Patriarch [[Shimun XXI Eshai]], born into the line of patriarchs at Qodchanis, had agitated for an independent Assyrian state. Following the end of the British mandate in 1933{{sfn|Cross|Livingstone|2005|p=354}} and a [[Simele massacre|massacre]] of Assyrian civilians at [[Simele]] by the Iraqi Army, the patriarch was forced to take refuge in [[Cyprus]].{{sfn|Baum|Winkler|2003|p=144}} There, Shimun petitioned the [[League of Nations]] regarding his people's fate, but to little avail, and he was consequently barred from entering Syria and Iraq. He traveled through [[Europe]] before moving to [[Chicago]] in 1940 to join the growing [[Assyrian–Chaldean–Syriac diaspora|Assyrian diaspora]] community there.{{sfn|Baum|Winkler|2003|p=144}}

Due to the church's and the general Assyrian community's disorganized state as a result of the conflicts of the 20th century, Patriarch Shimun XXI Eshai was forced to reorganize the church's structure in the [[United States]]. He transferred his residence to [[San Francisco]] in 1954, and was able to travel to [[Iran]], [[Lebanon]], [[Kuwait]], and [[India]], where he worked to strengthen the church.{{sfn|Baum|Winkler|2003|p=147-148}}

In 1964, the patriarch decreed a number of changes to the church, including liturgical reform, the adoption of the [[Gregorian calendar]], and the shortening of [[Lent]]. These changes, combined with Shimun's long absence from Iraq, caused a rift in the community there, which led to another schism. In 1968, traditionalists within the church elected [[Thoma Darmo]] as a rival patriarch to Shimun XXI Eshai, forming the independent [[Ancient Church of the East]], based in [[Baghdad]], [[Iraq]].{{sfn|Baum|Winkler|2003|p=148-149}}

In 1972, Shimun decided to step down as patriarch, and the following year he got married, in contravention to longstanding church custom. This led to a synod in 1973 in which further reforms were introduced, the most significant of which included the permanent abolition of hereditary succession — a practice introduced in the middle of the fifteenth century by Patriarch [[Shemon IV|Shemon IV Basidi]] (who had died in 1497) — and it was also decided that Shimun should be reinstated. The second matter was supposed to be settled at another synod in 1975; however, Shimun was assassinated in November 1975 by an estranged relative before this could take place.{{sfn|Baum|Winkler|2003|p=149}}