Complex sentence: The armies of Babylonia under Hammurabi were well-disciplined, he turned eastwards and invaded what was a thousand years later to become Persia (Iran), conquering the "pre Iranic" Elamites, Gutians and Kassites.
Split into simpler sentences: The armies of Babylonia under Hammurabi were well-disciplined. He turned eastwards and invaded what was a thousand years later to become Persia (Iran), conquering the "pre Iranic" Elamites, Gutians and Kassites.