In the RMRS we have been wrestling with this problem for some time. The staggered block idea looks nice in diagrams but in reality could easily lead to the two opposing lines fitting into each other like jigsaw pieces, meaning that everyone would outflank (and be outflanked by) everyone else, which could lead to a chaotic, indecisive and very bloody battle. Our preferred solution is that the units behind the line of battle might be drawn up in close order and in a chequer-board fashion, allowing individual units to be moved left or right according to where they would need to enter the front line when exchanging with troops already fighting there. The chequer-board arrangement would also allow units to expand out to the width they would take up in the battle line before actually entering it. Units fighting in the line would need to have expanded to the correct width before entering combat as it would be an extremely risky exercise to try and expand once already committed. The picture we have then, is of the front line fighting in close formation, but not as close as they would be on the march, giving each man enough space to move. The front line unit would be several ranks deep (anywhere between ten and four for a unit of century strength , depending on how much they had had to expand) and so any gaps in the line created by casualties or sideways movements of individuals during the riggers of combat could easily be filled by men from the ranks behind. With discipline and sufficient training we feel that it would be quite possible for a unit in close (but not tight) order to pass though another in the same order. With the relieving unit already expanded to the correct width, files of relieving soldiers could pass between the files of committed soldiers right up to the fighting line. The committed unit could then withdraw between the files of the relieving unit. This would be most difficult at the battle line itself but if each man had a small amount of space around him to allow movement enough to fight then a relief soldier would be able to close up this space (thus momentarily creating an unbroken front) and then let him withdraw with his unit, the reliever being committed before the already committed soldier was relieved. In battle this would be difficult to achieve successfully every time but a blast on the cornu (let's not forget that every century had one) could signal a relief and thus give a committed soldier warning to expect a reliever to turn up next to him.<br>
In all probability we feel that the entire fighting line would not be exchanged at the same moment, but rather, that the exchange would 'roll' along the battle line, with one exchange starting as another was still underway further down the line. The amount of space for units to expand behind the front line would be limited and so it seems sensible to think that they might have expanded and gone forward in turn. Retaining the chequer-board pattern would allow other units not expanding to allow space for those who were and would also provide wide corridors for battle scarred and exhausted soldiers to move down after being withdrawn from the front line.<br>
Now, I appreciate that this might all seem a bit too neat and tidy, but we know that they had the ability to move troops in and out of the fighting line and the obvious inference is that this was something they trained for on the parade ground. Such an operation would require a great deal of discipline and practice, but then, they trained for three hours ever day surely (and the concept of the weekend hadn't been invented then), and was it not them who gave us the word 'discipline'?<br>
We have tried the method of exchanging lines described above with four ranks, each of six men, treating each rank as a unit. Initially, and for the first four or five attempts, it was a shambles. Then, as we continued to try to get it right we got better, and by the end of around two and a half hours on a cold March day we had it to the point where we probably could have done it with our eyes closed.<br>
There are two caveats here. Firstly, we were exchanging single ranks rather than whole units, and secondly we were nowhere near a real combat zone. We can come some way towards answering these by acknowledging that we practiced it for just two and a half hours while a real Roman unit could have spent eight and a half times that amount of time getting it right in a single week; and by acknowledging that although the Romans did engage in violent and bloody warfare, like most modern soldiers, their main experience of field maneuvers would have been on the training ground, well away from any enemies who might interfere with the drill sergeant's morning!<br>
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We do not pretend that this method of exchange was the one actually used by the Roman army, but we do offer it as a possible solution to a problem. Any comments would be appreciated.<br>
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Crispvs<br>
RMRS <p></p><i></i>
