Roman Army War College

[Longovicium]

Glad to help. AHM Jones' work 'The Later Roman Empire' provides much needed background to the development of the corps of the Domestici et Protectores which indeed formed a sort of staff college and which in theory provided all units with commanders (practice being different of course). In time, it devolved somewhat into a sinecure and many people bought commissions because of the privilege of the rank rather than a desire to serve in the army. As with all knowledge about the military of the later empire, however, I think it fair to say that there are frustrating gaps which leaves much of the structure and development of the corps frustratingly opaque!