The 1,000 man legion

[John M McDermott]

188.000 - army of Maxentius, 312 AD (Zosimus II.15.2)
165.000 - army of Licinius, 324 AD (Zosimus II.22.1)
130.000 - army of Constantine, 324 (Zosimus II.15.2)
130.000 - army of Licinius at Chrysopolis, 324 (Zosimus II.26)
100.000 - army sent to Africa 457 (Procopius Bella III.6.1)
98.000 - army of Constantine, 312 (Zosimus II.15.1)
70.000 - army of the rebel Gildo, 398 (Orosius VII.36.12)
65.000 - main Roman army in Persia, 363 (Zosimus III.13.1)
50.000 - garrison of Egypt, 269 (Zosimus I.44.1)
35.000 - army of Licinius at Cibalae, 317/8 (An. Val. I.5.16)
30.000 - army of Macrianus, 261 (SHA, Gall. Duo II.4)
30.000 - army of the magister peditum Barbatio, 357 (Lib. Or. 18.49), Ammianus has it at 25.000 (AM XVI.11.2)
30.000 - army of Procopius, Persia 363 (AM XXIII.3.5)
30.000 - Roman army in Armenia, 543 (Proc. Bella II.24.16)
25.000 - army of Galerius in Persia, 298 (Festus Brev. XXV)
23.000 - army of Julian, 360 (Zosimus III.10.2)
20.000 - army of Constantine at Cibalae, 317/8 (An. Val. I.5.16)
20.000 - army of Vetriano, 350 (Jul. Or. 2.77B)
20.000 - army of Procopius, Persia 363 (Lib. Or. 18.214) though Zosimus has it at 18.000 (Zosimus III.12.5) and Malalas at 16.000 (Chron. XIII.21)
20.000 - Roman army in Mesopotamia, 531 (Proc. Bella I.18.5)
15.000 - Roman army in Africa, 533 (Proc. Bella III.11.2)
15.000 - Roman army in Illyria, 548 (Proc. Bella VII.29.3)

Before we go farther, we might ask which of these armies was commanded by a general and which was commanded by an Emperor?

Also, the preponderance in this list is for armies to be about 20,000.

Also, one is listed as the army of the rebel Gildo, numbering around 70,000.

This, of course, does not even begin to question the accuracy of the numbers, or, how long the "general" in question was allowed to retain command.

Then again, there are lies, damn lies and statistics.

The system of command in the Republic was for the Senate to appoint one of its number to command a Roman Army, regardless of its size. Power was dispersed into the Senate and to some degree to the people by plebiscite.

In the early Principate, Roman Emperors (who didn't necessarily call themselves by that name) appointed family members to command. Later, generals not related to the Emperor, and not necessarily Senators were named by the Emperor to command, and, thus began the period of renegade generals who pretended to the throne.

As the institution of the Senate waned and the last vestiges of Republican power were extinguished, all power came to reside in the Emperor. Any time he appointed a general to command an army, he was allowing power to revert to someone not himself, always an inherently dangerous thing for an Emperor to do. It should also not be forgotten that popular and successful generals could end up dead at the hands of the Emperor.

Lastly, the question ought to be raised as to the quality of troops allowed to be commanded by someone other than the Emperor. Were these armies well funded and well equipped? Was there quality equal to those commanded by the Emperor himself?

I believe Goldsworthy's valid point is that large armies tended to be commanded by the Emperor personally, a by-product of which was that the Emperor himself could be imperiled when a battle was lost.