The Persian Empire of the
Achaemenid Dynasty was at its height the most powerful force in the known world, incorporating a variety of cultures and peoples. It was a mighty state that could raise troops from many peoples, one of these being the
Assyrians. The Persian policy of granting limited self-government to its subject peoples gave rise to the Persian province of Assyria. The Persians did not call this province Assyria - rather, the lands were split East and West. The Eastern half was named Media (Māda), whilst the Western half was known as Athura (AӨūra). This article concerns these two provinces as an "Assyrian Province" of Persia.
See more at Wikipedia.org...