Auxilia Palatina

[Thiadricus Saxonicus]

Hi
I just wondered what the differences between trooptypes in the late roman field army might have been like.

We know of legiones palatinae, auxilia palatina, legiones comitatenses and legiones pseudocomitatenses.

I guess that the legiones would have differed only in the quality of their soldiers and equipment, yet fullfilling roughly the same tactical and strategical tasks as a heavy infantry.
What about the Auxilia now? Where they heavier or lighter? Did they use more missile weapons? Where they able to fullfill different tasks on campaign and on battlefield?
They are described to have fewer numbers, the legiones should be at 1000 men and the auxilia at 500. They consisted to a greater part of germanic soldiers then other units.
So I thought that they might be used for skirmishing action, as a light infantry. Yet at Strasbourg, Julian had them at his flanks and they withstood heavy frontal attacks by the Allamans, like a heavy infantry would be able to do.
And if they didn't differ in any way from the legions, why would they be called auxilia and not legion? And why did they rank so high in the late roman military hierarchy?
Information in the books I read was always quite scarce, so I hope someone here knows more

[Thiadricus Saxonicus]

So no one knows which tasks the auxilia palatina would perform in the late roman army?

[Robert Vermaat]

I guess that the legiones would have differed only in the quality of their soldiers and equipment, yet fullfilling roughly the same tactical and strategical tasks as a heavy infantry.

Most likely, yes.

What about the Auxilia now? Where they heavier or lighter? Did they use more missile weapons? Where they able to fullfill different tasks on campaign and on battlefield?

Both, yes and yes.
Auxilia were the same and yet not the same as the 'ancient' auxilia. They differed in the manner that:
a) every person inside the Empire was now a Roman and therefore the differences between legions and auxilia vanished, plus
b) Romans as well as foreigners could and did serve in every unit sort and type.

Yet they also resembled the 'old' auxilia. The 'new' auxilia were elite units, or had been set up as such in the later 3rd c., and could serve as both light infantry and heavy infantry, which was exactly the same as their pedesessors had served. Remember the Batavi at Mons Graupius? Indeed. In fact, the Late Roman infantry had been changed to resemble the role of the old auxilia, in the manner that they could assume several tactical roles instead of 'just' heavy infantry. This also goes for the Late Roman legions.

So I thought that they might be used for skirmishing action, as a light infantry. Yet at Strasbourg, Julian had them at his flanks and they withstood heavy frontal attacks by the Allamans, like a heavy infantry would be able to do.

Exactly. They could and did both.

They are described to have fewer numbers, the legiones should be at 1000 men and the auxilia at 500.

Nicasie estimates border legions at 3.000 men (down from 5.000), while new-style legions of the field army numbered up to 1.000 or 1.200. Vegetius' legion strength of 6.100 infantry and 726 cavalry (Vegetius II.6) is thought to belong to 3rd-c. legions, not to 4th-c. legions.
According to several remarks by Ammianus, legions were quite a bit smaller, between 1.00 and 1.500 each.
We can guess what strengths may have been by guesswork - 300-500 men in a vexillation, 12 legions in a relatively small expedition, 300 men routing a legion, 400 men being heavy casulaties during a sorite from besieged Amida (which harboured 7 legions, citizens and refugees, all together numbering 20-25.000).

Cohorts seem to range between 300 and 500, but we hear of legions formed usually by two cohorts. Cavalry units could be anything from 300 to 700. larger units of 1.00 to 1.500 were probably several smaller units combined. Maurikios puts the ideal number between 300 and 400.

They consisted to a greater part of germanic soldiers then other units.

Maybe and maybe not. The later you get, the more you see the practise of hiring german groups wholesale, but that's around 400, not before. Elton has found no evidence for the popular assumption of the 'Germanization' of the Late Roman army.

And if they didn't differ in any way from the legions, why would they be called auxilia and not legion? And why did they rank so high in the late roman military hierarchy?

Just names. You have auxilia palatini as well as legiones palatini. Both rank high in the LR military hierarchy.

Read also this thread about LR auxilia.
Read also this thread about numbers etc.