Assyrian Army of the Sargonid Period
The Assyrian army in the Sargonid period had a potential magnitude of several hundreds of thousands of troops, although a call-up of the entire force for a campaign was extremely rare. Supreme command of the army rested with the king and, immediately under him, the “field-marshal”…. The army was divided into units of various sizes and types; but the basic division was the “company”…of fifty men under a “captain”…and this unit was in turn broken down into files of ten men. An officer carried a mace as a symbol of his authority.
The levying of troops was the primary responsibility of the captains, each of whom had a certain number of villages under his command, and the captains were in turn responsible to the provincial governor. By the Sargonid age there was also a standing army which was under the direct authority of the king, no doubt created as a counter-balance to the potential misuse of military power by the provincial governors. The king also had his own bodyguard of infantry and cavalry. The troops recruited within Assyria proper were spread around the empire as much as possible, since they were the most loyal, and they constituted the chariotry and cavalry divisions. The infantry consisted largely of foreigners, mainly Aramaeans. Some foreign groups became specialized units. For example, the Ituaeans, an Aramaic people, were entrusted with special tasks such as escort duty throughout the empire.
Garrisons and barracks were scattered over the empire, but the military headquarters was a massive armoury in the Assyrian capital. Here was stationed a large portion of the troops, animals, and equipment of the standing army, and there were, in addition, royal apartments for the king to occupy when he wished. At each New Year there was a grand inspection at the armoury when the king reviewed his troops and their equipment….
— The Cambridge Ancient History, volume III, part 2