When was Roman army at the height of its power?

[Frank]

How is the Augustan army more "centralized" than the 2nd century army? Legions were placed on the border, if anything the army of Constantine would be the most "centralized" via Comiatenses.[quote]

Until Domitian you had double legion camps. You also had more legions under command of a single legatus augusti pro praetore, because some provinces like Pannonia were not splitted yet. And until Claudius' adventure in Britannia you had 3 legions more at the Rhine border. Also the overall distribution of the legions is different. The defensive stance of the roman army is not fully developed during Augustus' reign.
Of course there was no central or regional field army like in the late empire, but some province governors had an comparable exercitus.



[quote="Andy" post=347084]Hmm the Era of the Good emperors saw the most stable economy and political structure.

There is archaeological evidence form analyzing shipwrecks, trash montains near Ostia and such, that the economy of the empire saw a massive change during the 2nd century. Markets and flows of commodities changed dramatically. In Italy and Spain for the worse, in Gallia and Africa for the better. Some historians explain this with globalization effects due to the common economic zone and currency. We should not call it decline yet, but the roots for the economical crisis in the 3rd century are versatile and some processes started already very early.

I also don't see fundamental differences in the political system of the 1st and 2nd century. The political stability from Nerva to Commodus was rather luck than based on political measures.

I would call the 2nd century the Silence before the Storm.