The Battle of Pharsalus:
Deployment of the Armies

The infantry deployment has already been worked out. What remains is to attach the cavalry and skirmishers in formations that are credible.

The initial deployment is shown above projected onto the map of Pharsalus. For the purpose of developing the deployment configuration the Pharsalus map has been tilted so that the armies are in the more customary horizontal orientation. The river is on the left, the foot of the hill is on the right. The green contour line on the left indicates a rise in elevation of 20 meters between the river and the line. . The infantry and cavalry would be on almost flat ground gently rising ground.

Deployment of the Cavalry

The 7,000 cavalrymen of Pompey's army are a challenge to try to deploy. The enlarged image below will help visualize the problems.

This formation is simply a display of the national units that were imagined to have composed Pompey's cavalry. But even so, the problems in modeling become apparent. As the formation now stands, there are 8 lines of turmae, each with 3 ranks of horsemen. That gives the formation a depth of 24 ranks. The usual description of cavalry is that is was used in wide shallow formations, only 3 or 4 ranks deep per line, perhaps a couple of lines well separated from each other. Clearly, that formation would not be possible given the terrain limitations. Nor would it seem particularly likely. If Pompey's cavalry were arranged in two long ranks it would be 7 times as wide as Caesar's cavalry line; it would be approximately as long as both the infantry and the cavalry on these illustrations. Even on perfectly flat ground such a formation would be improbable.

Pompey's cavalry formation will be held to approximately the width shown above. The national units will be re-arranged into blocks rather than lines to give them a bit more cohesion. The drawing below shows a better deployment. The national units have been arranged into formations two lines deep and colored to help distinguish one from another. The three lines of cavalry are separated by 50 yards each. Immediately behind the third line are the cohorts of slingers followed by those of the archers, now arranged in to lines themselves.

On the other side, Caesar's cavalry is now shown split into two parts with the light infantry cohorts interspersed. This was done to give the whole formation more width.

Behind the infantry formation on the left the 6 cohorts Caesar held as a 4th line are shown in an angled formation. This is not a wholly satisfactory arrangement for these 6 cohorts. The idea seems to have been that they took Pompey's cavalry by surprise. If Caesar's cavalry is pushed back out of the way it is hard to imagine how these 6 cohorts could be a surprise to Pompey's men. Here are four possible configurations for these 6 cohorts.

Upper Left: Angled line -- the cohorts align at an angle and then simply charge straight ahead.. Pro: it is easy for them to attack from this position. Con: it is not hidden, there is no surprise, why wouldn't Pompey's cavalry attack it as well as the flank of the other three lines?

Upper Right: Wheeling attack-- the cohorts line up behind the third line and wheel around to attack. Pro: they are well hidden. Con: it would be difficult, probably impossible, for the 6 cohorts to attack by turning around, then wheeling in formation 180 degrees.

Lower Left: Out and up -- the cohorts run out to the side, turn to the front and attack. Pro: the cohorts are hidden and do not have to execute a turning maneuver. Con: the turning maneuver may be too much to expect.

Lower Right: Oblique attack -- the cohorts line up quite far behind the third line and attack at an oblique angle. Pro: there are no turns to make and the cohorts may be far enough back to be considered "hidden" in as much as they may escape the notice of the cavalry. Con: the cohorts as shown are 1,400 feet behind the third line. This would be too far for them to mount a charge, certainly much to far to run.

However, in all of these scenarios the cohorts have a considerable distance to move. The line of the 6 cohorts themselves have a length of 950 feet. Upper left -- it is 1,000 feet from the rightmost cohort to the back of the third line. Upper right -- the cohort on the left, with the longest distance to cover in the wheeling motion, would have to travel over 2,400 feet. Lower left -- the minimum distance they would have to run to the side would be their own line length, 950 feet, then turn and attack to the front.

If the 6 cohorts are to attack quickly and at a running charge they can be required to run no more than 200 feet. This places severe constraints on how they can be arranged.

This illustration shows some of Pompey's cavalry in a position to attack Caesar's right flank. The cavalry have turned so that they now face to the left. At the bottom the 6 cohorts are shown with a blue box in front of them. The box is 200 feet deep, the maximum distance the cohorts should be expected to run to attack the cavalry.

They cannot have actually been in the position shown. In the first place, they would have been in the cavalry's way earlier. In the second, they would hardly be able to take Pompey's cavalry by surprise.

Another way of approaching the problem is needed.

This solution is only marginally better than the others. By moving the remaining two cohorts of line three to the left there would be room for an inside swing to bring the cohorts into contact with the charging cavalry. The distances moved are within reasonable limits. Only four of the six cohorts are in contact with the cavalry. It might not be too much of a stretch to imagine the two cohorts on the end turning and wheeling more to the side and the remaining four taking an inside turn. Against this solution is the complexity. This was a spur-of-the-moment decision by Caesar. These cohorts came from different legions and would not have drilled together. Their ability to coordinate their movements would very likely have been limited to quite simple maneuvers. Unsatisfactory as it is, this is the configuration that will have to suffice for the rest of the model.

It is not only the deployment of the six cohorts that is questionable. The deployment of the cavalry and skirmishers is so speculative it is hard to say it represents what Pompey and Caesar saw that day, or that it is a reasonable interpretation of the information, or even that it is a feasible configuration. Nevertheless, it is the best configuration I could come up with for the model.

Next Page: The Battle of Pharsalus: Pre-Battle

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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.