 The ancient Chaldeans seem to have migrated into Mesopotamia sometime between c. 940–860 BCE, a century or so after other new Semitic arrivals, the Arameans and the Suteans, appeared in Babylonia, c. 1100 BCE.They first appear in written record in the annals of the Assyrian king Shalmaneser III during the 850s BCE.This was a period of weakness in Babylonia, and its ineffectual native kings were unable to prevent new waves of semi-nomadic foreign peoples from invading and settling in the land.