Dinkha established headquarters—along with four other houses of worship—in Chicago, Illinois, United States, in part due to the instability of the Iran–Iraq War. This conflict as well as Saddam Hussein's policy of Arabization in Iraq, the Gulf War and subsequent sanctions against Iraq intensified the Assyrian diaspora from the region. Meanwhile, the Islamic Revolution and Shia emphasis in Iran created a tense situation for Assyrians in the Middle East. During the reign of Shimun XXI and Dinkha IV, American membership in the Church of the East rose from 3,200 in the 1950s to approximately 100,000 in 2008.