The modern nation of Iraq, is a recent concoction. The region was originally part of the Ottoman Empire for centuries, but the British established what we know of now as Iraq, in 1932 cobbling together Kurds from the north, Sunnis around Baghdad and a Shiite Majority in the south.
https://en.wikipedia.org/wiki/History_of_the_Middle_East
Mesopotamia was home to several powerful empires that came to rule almost the entire Middle East—particularly the Assyrian Empires of 1365–1076 BC and the Neo-Assyrian Empire of 911–605 BC.
Assyrians predated the Ottoman empire by a huge time span. Christians were in Assyria from the time of Christ.