The Late Roman Army

[Robert Vermaat]

an example...I know the troops used the spatha and there are several throwing weapons, like javelins, plumbatae a.s.o., then we have troops using the lancea and other things. is there any source ro else indicating which type of infantry used which weapons? did they differ within units? is there any kind of standardized equipment for lets say limitanai or comitatenses? it doesn't seem to me that the stationary troops were that much worse equipped than the field army at least during the 4th century.

No, there is no standard equipment for the units you mention. Of course there were specialist troops such as archers and slinger and so on, but the status of the units (comitatenses vs. limitanei) would not have mattered. We think the former had first choice in equipment, but the sort of equipmement would have been the same. Standard units had different roles though, in which equipment could change. Infantry could fight with the sword but could also act as phalanx, in which the lance had a primary role. But we also know of nightly commando-like raids, where heavy stuff like helmets would have been left at home.

btw if anyone could tell about personal experience with late weapons (use of the spatha for inf or plumbatae) that would be interesting as well.

I've thrown javelins, I've thrown plumbatae, I did a small bit of spatha fencing. Plumbatae (as you maybe know) are my absolute favorites, and also the most typical of Late Roman weapons. I recently made a few. The lance is also an awesome weapon. Mine is 4 ft - any longer and it won't fit in the car, mostly the reason why most re-enactors have too short lances
Ask Mithras about his heroic marches in Late Roman gear!

and my special interest lies in the army of the divine emperor Iulianus because I'm going to write a paper on that but anything else is great as well.

Read the works of Ammianus marcellinus, the best author we have on this topic, and a big fan of Julianus to boot!