Most of Iraq’s Christians call themselves Assyrians, Chaldeans or Syriac, different names for a common ethnicity rooted in the Mesopotamian kingdoms that flourished between the Tigris and the Euphrates rivers thousands of years before Jesus. Christianity arrived during the first century, according to Eusebius, an early church historian. From Greece to Egypt, this was the eastern half of Christendom, a fractious community divided by doctrinal differences that persist today: various Catholic churches, the Eastern and Oriental Orthodox, and the Assyrian Church of the East. When the first Islamic armies arrived from the Arabian Peninsula during the seventh century, the Assyrian Church of the East was sending missionaries to China, India and Mongolia. The shift from Christianity to Islam happened gradually. Much as the worship of Eastern cults largely gave way to Christianity, Christianity gave way to Islam. For 1,500 years, different religions thrived side by side. One hundred years ago, t