[split] Distances between files and ranks

[Nathan Ross]

For me, a 120 maniple has a frontage of 60 men and a depth of 2 men. Therefore, a century is arrayed 30 men wide by 2 men deep. In this manner, the centurion and optio can do their job and be where they need to be, when they need to be.

Without wanting to go too deeply into complex issues, I'm wondering why you are suggesting such a long thin line? Surely the centurion would find it a lot harder to give orders and even see what his men were doing when they were so stretched out; advancing would cause difficulties too, as a thin line would bow a lot more than a deeper formation.

If we assume that the century trained together and generally acted together, surely arraying them deeper would have been more effective than having to rely on men from other centuries drawn up (presumably) behind them?

Arrian has the cavalrymen belonging to their infantry units being arrayed in a single file on both flanks of the infantry, which are four men wide. This would increase the frontage of the column from four men to six men.

I know we've discussed this before - a horse takes up a lot more space than a man, so it would be hugely impractical to have your infantry marching abreast with cavalry, if that's what you're suggesting here! Besides, if we're assuming that the column could deploy from line of march, having infantry mixed up with cavalry like this would cause problems.

What Arrian means, I think, is that two separate flanking lines of cavalry paralleled the main infantry column. They would not be part of the main infantry column.

Arrian also specifies four men wide when marching... changing from march order to battle order in one movement.

Exactly. This is why I would consider that Josephus's six-wide column (if he was right about that) implies a six-deep formation, which might in turn imply a change from a 60-man to an 80-man century at some point. But that's another question entirely!

Metellus halted his army, and changed its march order formation... with three lines of reserves... (The Jugurthine War 49 4-6)

Yes. This seems to be a good description of changing from march to battle formation, and I don't see anything controversial about it. We don't know whether the 'lines' (acies, I think) that Metellus brought up were lines of maniples, or individual men, or what - I suspect maniples. It would be interesting to know how wide his march column was before that!

But what he's doing is massing his men into a thicker column and wheeling them round to form a battle line, so his vanguard and rearguard are now on the flanks.