The Immortals

[Aryaman2]

I belive that yo need some sort of military complexity and ogranization to maintain a vast empire. If the Persians did not made something original theyt had the experience of the former Assyrian and Babyloninas before them.

Kind regards

Some sort, but what sort? The Spanish Empire in the 16th century encompassed huge distances, however it had no permanent units above the administrative level of Tercio (1.500 to 3.000 men) and tactically not above the company (150 strong). A vast empire does not necessarily requires large permanent army units, it depends on the military technology and organization.