Roman Legion in late Antiquity

[Nathan Ross]

The statement that Severus 'doubled the size of the Guard' (whilst I would really appreciate an ancient reference from anyone, I have seen this mentioned before) - could that not equally mean that he 'added to the 10 cohorts of the Praetorian Guard the 10 cohorts of the II Parthica

Hmm, interesting - you could well be right!

It seems the idea about Severus doubling the size of the guard (by increasing the numbers in a cohort, not the number of cohorts) comes originally from Herodian, who wrote that Severus 'quadrupled the number of troops at Rome'. Durry (in Les Cohortes Pretoriennes of 1938, which I haven't read) seems to have been the first to suggest that this meant an expansion of size for the praetorians, urbani and vigiles combined (although how that 'quadruples' them I don't know!). This was supported by Birley (Septimius Severus and the Roman Army, 1969), and accepted by Field (Army Reforms... in Historia, above). But of course Herodian might have been exaggerating - or, as some others more recently have suggested, he could indeed have been adding II Parthica to the 'troops in Rome'!

Assuming you mean the Marius of the 'reforms' (c105BC) - then legions of 60 centuries can easily be read as 60 x 100 and an author (without detailed knowledge) therefore, not entirely unreasonably, equating to 6,000.

I've read that 'Marius 6000-man legion' thing in several places. Doesn't it come from Livy? (republican history is a bit of a grey area for me!) I notice that the exceptor of Festus writes sex milium et ducentorum hominum legionem primus Gaius Marius conscripsit... :-|