[split] Distances between files and ranks

[Nathan Ross]

If these were lined up 12 deep that would have been 40 metres wide in close order... so a width of 500 metres for the Legionaries of the Legion would seem to be logical.

Or 60 metres wide if they were 8 deep. Arrian seems to think this was dense enough to repel cavalry. Vegetius has his cohorts in two lines rather than the triplex acies familiar from the republic. An 8-deep close-order formation (perhaps two lines four deep?) would give the legion c.600-625 metres width.

The double first cohort was probably a Flavian innovation, but there may have been a (cohort-sized?) veteran vexillatio attached to the Julio-Claudian legion; however, I suggest these might have been used as reserves behind the centre, rather than joining the front lines.

As for Suetonius Paulinus, I would think he would deploy his men (within reason) to fit the width of the defile, rather than choosing only a defile that would fit a certain standard width of formation.

how would the cohorts of men transition into the “wedge formation” from “closed” formation on the battlefield... how did they manage this, at speed... or was the charge a more deliberate advance?

Some descriptions of the cuneus imply an advance in a column - which would either mean changing formation (unlikely) or a strengthened centre that could push outwards into the midst of the enemy. This might have been the purpose of the veteran vexillationes - if they were posted at the rear they could have provided the mass to support a charge by column from the centre of the line.

I would say more a 'deliberate advance' though. They would have wanted to keep formation, and would have been fighting as they went and clambering over any obstacles in the way too, so at jog at best, I would think, speed-wise!