You may have noticed that Upper Nile is South of Lower Nile. This is because the Nile flows from South to North on it's way to the Mediterranean Sea. Upper Nile is upstream, Lower Nile is downstream.
The kingdoms of the Upper and Lower Nile combined to form Egypt. The land between the Euphrates and Tigris rivers became the kingdom of Sumer.
Sumer became Babylonia and Egypt extended into Syria. Assyria gained control of Babylonia, Mesopotamia, Syria, and Egypt. Eventually Assyria was overcome by the Neo-Babylonian or Chaldean Empire
At the end of the seventh century, Assyria adopted Christianity, which later split into several branches including the Chaldean Church.
Starting in the sixth century BCE, Cyrus the Great founded the Persian Empire, conquering much of Southwest and Central Asia