Assyrians were some of the British Administration 's most loyal subjects , and so they employed Assyrian troops ( " Iraq Levies " ) to put down Arab and Kurdish rebellions in the aftermath of World War I and to protect the Turkish and Iranian borders of British Iraq from invasion . In consequence , Assyrians of all Christian denominations endured persecution under the Hashemites , culminating in the Simele massacre in 1933 , leading thousands to flee to the West , in particular to the United States . Patriarch Shimun XXI Eshai himself went into exile in 1940 – 1941 and relocated the patriarchate to Chicago which became the centre of the Assyrian – Chaldean – Syriac diaspora . However , the Assyrians who remained continued to work alongside the British , even playing a major role in bringing down the pro-Nazi Iraqi forces during World War II , and remaining attached to British forces until 1955
Simele massacre
Simele massacre
Assyrian Church of the East