Office system for EB?

[Atraphoenix]

Because of the fact that it will take hours even days to search just an office especially used by a faction I am indecisive to use English titles or native titles:

for example : unsure about what was the generalissimo of Parthians;

George Rawlinson : The Seven Great Monarchies Of The Ancient Eastern World, Vol 6. (of 7): Parthia

There were probably several grades of rank among the nobles. The highest dignity in the kingdom, next to the Crown, was that of Surena, or "Field-Marshal;" and this position was hereditary in a particular family, which can have stood but a little below the royal house in wealth and consequence. The head of this noble house is stated to have at one time brought into the field as many as 10,000 retainers and slaves, of whom a thousand were heavy-armed. It was his right to place the diadem on the king's brow at his coronation. The other nobles lived for the most part on their domains, but took the field at the head of their retainers in case of war, and in peace sometimes served the offices of satrap, vizier, or royal councillor. The wealth of the class was great; its members were inclined to be turbulent, and, like the barons of the European kingdoms, acted as a constant check and counterpoise to the royal dignity.

I thought that parthians used "Spahbod" or "Spehbod" for chief commander.