Visualizing the Line of Contact between Armies

Once one does away with the neat little boxes and straight lines the whole visualization of the battleline changes. It is very difficult to model the battleline in any detail.

This page is an effort to look at the actual line of contact between opposing Roman forces and try to understand the mechanics of the encounter.

(1) These three frames show three centuries each at the initial charging position -- 150 feet apart. They have arrived at this point by marching and are presumed to have been able to stop in place here for instructions and also to re-dress the lines. Two centuries are a prior/posterior pair separated by 6 feet, the other century is 12 feet away. Some gaps are necessary for maneuver. The distances of 6 and 12 feet were picked because they were multiples of the 3 foot file spacing. Without observing some experiments it is difficult to know how large a gap might be necessary. It could well be that these formations could not have marched and run over uneven ground in the face of enemy fire without bumping into each other if they only had these relatively small gaps.

(2) ........................................................... (3) ......................................................... (4) .

(5) Frame (3) shows them 60 feet apart, where they would throw their pila. The third frame is when they first come together.

As the formations run together the spacing changes. The blue centuries squeeze together, the red ones spread out a little. Something like this would be inevitable. In the third frame the middle red century is back just a little, they didn't start as quickly or ran slower -- again, this type of thing would be inevitable.

Below is a closer look at (4).

(6) There would presumably be other formations to the right and, without including them in the frame, it is not possible to model the right three files of the red century. The purple curved line shows the edge of where the model can effectively show how the formations might have moved. Three files of another blue century are shown on the right just to make the point that there would be another century on that flank.

The points of interest are just what happens in the middle of this picture where the blue century overlaps the red and where the red century is further away. The next illustration attempts to show how the ranks and files might have adjusted.


(8) The gaps have not yet been closed. During the charge the men have to focus on throwing their pila, drawing swords, attacking etc. They can't worry about spacing between centuries. Therefore, when they hit each other there are gaps, units overlap, some face empty space. Up to this point they can't adjust -- they can't move sideways without bumping into someone, and they really don't know how the enemy formation might line up against them until it is too late to make any adjustments anyway.

(9) The middle blue century continues forward until it meets up with the red. Where there was overlap the files of the blue century continue forward into the open space. As this happens the 2-4 rankers shift position to cover their flanks. There is no time for the back rank to move into the gap. The time interval between the throw of the pilum and this frame would not be more than about 3 seconds, maybe not even that.


(11) This is a further development of (7) showing how the riles begin to fill in the gaps and how a battleline starts to form


(13) This is the final image in this sequence. The two sides have formed a more or less continuous front.

Fighting like this might continue for 3 to 5 minutes then the two sides would have to back off at least a little distance.

The next frame is going to skip over that and move to a point where the blue centuries have exploited the gap and made a dent in the line.


(15) This seems like a reasonable representation of the situation. In many places the ranks and file structure has broken down in the heat of hand-to-hand fighting. This would be inevitable, especially not if it were necessary to close gaps or exploit openings. The wedge shape in the middle will be of interest in further developing the models.

(16) This shows both sides having taken a step or two (five feet each) back from each other so that they are separated by ten feet.

(17) Some suggest that separating the two lines by as much as 30 or 50 feet is incorrect. All that would be required, they say, is enough separation so that the two sides could rest a bit. This does not seem adequate. Neither side could re-arm itself. The centuries could not re-group and re-dress their lines. Without restoring some order to the centuries it would be virtually impossible to mount any kind of organized rotation of the ranks to bring fresh men to the front. It would be difficult to mount a coordinated attack. Bringing water to the men or removing the wounded would be difficult in a situation as shown above.

(18) To accomplish any of these activities there needs to be more separation. The 60 feet of separation shown in the update pages may not be necessary but 30 feet would seem minimal. That is shown in the following image.

(19) At this point it would be nice to explore just how the centuries might restore order among themselves. The following next few steps will assign a color to each file to make it easier to distinguish them. The "red" army is still at the top of the illustration and the "blue" at the bottom but the colors will be changed to identify each file. Lines will be drawn between adjacent centuries. The centurions for each century will be indicated by symbols that are colored in.

(20) The question is how to depict the re-dressing of the centuries. The ranks and files would dress themselves on the centurion. He would, presumably, survey the situation and select a reference point for the re-dressing.

The position of some of the centurions should be noted. When the men in the back ranks began to fill in the gaps, image (10), the centurions ended up with one or two men on their right. This would seem an inevitable consequence of men filling in gaps but has not been previously noted in any descriptions of Roman fighting..

(21) First steps in re-dressing the centuries

(22) These changes are illustrated in section (23) below. Some new files have been added at the edges (colored the original red or blue) to fill out the edges of the frames.


(24) In the next frame the centurions begin to re-dress their ranks and files.

(25) The centuries begin to re-appear from the chaos of the previous illustration. What would be important here is to imagine just how each of the centurions would go about deciding upon an alignment for his men. If his century had penetrated the enemy line previously and so was in advance of those around it, would the centurion back his century up to resotre a more or less straight line? Or would he preserve the advantage previously gained and line up in a more forward position? Would those somewhat behind other centuries try to move forward to straighten the line? What would the red century at the top do about the wide front it has to fill? As shown, the centurion is bringing the files together toward him, leaving a gap between his century and the one to our left as we look at it.

(26) Each century lines up on the position of the centurion as sown in the illustration above. The next illustration shows the completed re-alignment.

(27) The centuries have been restored to pristine order (there are no casualties in this battle). Now what? Do they hold this formation or adjust themselves? I would see some minor adjustments at least. The red centuries might even out the spacing some. The centuries might seek to straighten out their lines some, but this illustration is deceptice. In considering just how much the centuries might re-align themselves it might be good to look at a wider piece of the battlefield.


(29) This illustration makes it clear that the blue and red centuries cannot simply line up side by side and re-form a straight line.

Just how the centuries on the right might align themselves was discussed in one of the update pages. This formation maintains an "north-south" orientation for all of the centuries. It keeps the battlefield neater. A difficulty arises when the centuries wish to mount a charge. The illustration below highlights the problem.


One blue century is shown making a straight forward attack against the red line. The problem is that the two centuries do not line up exactly. Half the blue century has nothing to attack. Nor could the century attack at an oblique angle for then it would be cutting across the front of its neighbor and utterly confusing the battlefield.

The alternatives mentioned there were to maintain a staggered formation like the one illustrated above or adopt a slanted formation as in the illustration below.


This illustration shows the same formation as (28) but with the centuries angled. A better view might be the one below, in which the centuries are shown side by side and aligned along the actual line of battle -- as they would have been before pulling back from each other.


(33) The problem with this type of arrangement arises when the centuries wish to pull back from the line. The red centuries would create wide gaps in their lines. If there were a second line of reserve/reinforcing centuries, then they could be moved in to fill the gaps.

The blue centuries actually have a bigger problem. Each rectangular formation can only be expected to back up in a straight line according to its own orientation. That is, it cannot be expected to back up sideways. Therefore, as they pull back they begin to bunch up, run into each other. The illustration below shows the two lines of (32) with 30 feet separation between them. To create the image each century was moved 15 feet perpendicular to its own front.


(35) If the centuries were to try to withdraw any further the problem of congestion could become acute. As is, the crowding could probably be taken care of by compressing the files. One might also argue that, if the blue line had made a penetration sufficient to cause this much of a curve then it would hardly be the line to retreat, any backing off would have to be done by the red line. When the red centuries back up they open up gaps, making their position less secure and forcing them to thin the ranks to fill in the spaces.

(36) How could the north-south facing centuries change to the angled orientation? The illustration below is number (14) above. It shows the beginning of a bulge. Since the two lines initially all face north-south the indifiduals in this illustration continue to face north-south even though some have penetrated the red line further. Even though the line of contact is slanted, the individual men and their files all continue to face north-south.

(37) For them to reach the position illustrated in (34) the individuals would have to turn and face to the oblique. Unless they did that, they would back up to the south and end up in the staggered formation illustrated in (26) . In fact, the whole sequence from (14) through (26) is based on north-south orientations. Just how and when would the men and their units assume a north-east/south-west orientation?

(38) The staggered formation has a problem with how local charges would be featured. The angled formation has a problem with showing just how the north-south orientation of the individuals, files and centuries gets slanted to the oblique.

(39) This illustration below is the same as (19) above. It may contain a clue as to how the slanted line (32) could begin to form. To get to an oblique century alignment the centurion (in this case the one of the right-most century of the blue army) could decide to dress his century on an oblique line. That is, looking at the the battlefield. The process is shown in several illustrations below.

(40) Below, the centurion picks his line and begins to get the first ranker's lined up along it and facing in the direction he wishes. The rest of the ranks start to move toward their new positions by simply lining up on the back of their first rank man.

(41) The ranks slowly reach their new alignments. At this point some are still facing north as they move toward their new positions, others have reached their places and have turned to face in the same direction as their front rank man.

(42) Once the ranks have reached their new positions they dress the ranks and files by restoring the appropriate spacing. This is probably done in a simple manner -- by entending one's arm to touch the man to the right or front. The illustration below shows the century restored to it pristine rank and file formation.

(43) The question is, is this a posbbile maneuver? First, could it have been done in the face of the enemy who, in this case, is a mere 30 feet away. At any point in the process is the century vulnerable to attack? Would the maneuver be too complicated to carry off? Would it take too long?

(44) The answers to all of these questions is "no." The maneuver is possible. But, is it plausible? Is this something that the centurion would do in the situation? How much latitude did the centurion have in making these decisions? How much of the battlefield could he see? Could he know that he needed to face his century to an oblique angle? On paper it may be easy to see a slanting line of contact between two forces. It may not have been at all easy to see from the vantage point of the actual battlefield. The question of plausibility is open to debate and ultimately depends on how one weights the various factors.

(45) Issues addressed and still open questions:

(46) Gaps in the line -- would there be small gaps in the line when hand-to-had begins? Yes. Gaps were necessary for maneuver and for the charge. They could not be completly filled before contact was made. Once contact happened the gaps could be filled but only by the closest ranks because there would not be time for the elaborate maneuver required to take men from the back rank and make them into a new file to fill the gap.

(47) Chaos -- once contact between the lines is made the rank and file structure disintegrates -- see illustration (14). It simply cannot be maintained in real-world situations. The need to adjust to gaps, uneven lines, mis-aligned enemy formations wholly preclude the retention of neat lines.

(48) Distance the two sides would need to separate. Ten feet would not be enough to allow the century to re-dress its ranks. If the armies did not separate further then the ranks and files would simply disappear and one is left with an unformed mass of men. This does not seem to match what we know of Roman battles. It would also prevent the proposed methods of using the pila of the back ranks since that would require some rank and file organization.

(49) Need to re-dress the lines. If the Romans preserved any unit cohesion or formations at all then there would have been an absolute need for them to re-dress the ranks and files of the century.

(50) Re-dressing on a north-south axis has benefits and problems. It is easier to accomplish, it retains the overall orientation of the army. However it also makes subsequent attacks against another Roman force also arranged in centuries more difficult to visualize. Against different enemies this might not be as large a problem, however the models do not address that because of a lack of information about those enemy armies. Against Romans, the misalignment of opposing centuries or cohorts would be inevitable. If they are misaligned and in a staggered formation then how does one visualize the attack when only half the attacking unit encounters enemy soldiers? See (30).

(51) Re-dressing on an oblique line solves the attack problem but at the cost of having the centurion make decisions he may or may not have been able to make given the conditions on the battlefield. Actually, this solves the attack problem only if both sides are on the oblique. If the enemy arranged its centuries in a north-south orientation as in (30) then the charge of the oblique formation would still encounter staggered formations, empty space, and the like.

(52) Are there other ways to visualize the battleline? Are men actually so fluid in their movements that the designation of ranks and files and discrete units becomes unimportant. That is, if they charge and there is only a partial overlap of opposing fomations -- could it be that this would not really be a problem for the soldiers? Both sides might simply adjust to the situation in a natural manner? Is yet a whole new, more fluid, method of visualization needed?

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© 2003, Gary Brueggeman. All rights reserved world wide. No part of this work may be reproduced in part or whole, in any form or by any means, without permission from the author.