High Imperial Roman army vs Late Roman army

[Flavivs Aetivs]

I disagree that the West had "no more a full working professional", or that the "names of the units quoted in the Notitia, after Frigidus, are only names written on the paper". I look forward to seeing evidence for that. I think that the West did have an army, but that Stilicho squandered that in a useless conflict with the East.

Well, only looking in your timeline, what happened in year 406 is something more than an evidence .... what the germanic invaders found or better did not find in Spain,it is something more than an evidence, in my opinion.

Look, reading the Notitia, In Spain there should have been 11 Auxilia Palatina and 5 legiones comitatenses under a Comes Hispaniarum, even half of this force probably would have been able to stop any invasion, so probably this force actually existed but sadly, ...... only on the paper.

You gave to understand that there were usurpations going on. The Barbarians were not just "invaders" but Opportunists. There was almost no Barbarian expansion under Aetius' reign, but the instant he was dead the Suebes siezed the rest of spain, the Visigoths siezed North Aquitaine, the Franks expanded south, and the various peoples north of the danube invaded Noricum.

With the usurpation in Britain in 406, and Stilicho being tied up with a war in the East, then the Barbarians knew the Roman Army was tied up and took the opportunity to cross the Rhine.

Furthermore, Spain was never meant to see combat - the Spanish army existed but was not experienced. they would have had highly trained, but no veteran soldiers and Generals. When Maxentius usurped in Spain in 413, he had a Spanish Army, so it certainly did exist, but it was not a capable force.