The Battle of Pharsalus: Pre-Battle

Army Dispositions on the Days before the Final Battle

On the days before the final battle Caesar offered battle to Pompey. Pompey deployed his men at the foot of the mountain to see if Caesar would subject himself to such an disadvantageous place [ad infima radices montis aciem instruebat semper, ut videbatur, exspectans, si iniquis locis Caesar se subiceret]. Morgan does not describe just where or how the armies were positioned at this phase of the battle.

The image below shows the simplest version of the positions on earlier days when Pompey lined his army up closer to his camp.

In this deployment Pompey's army is in the same orientation as it is for the day of battle but is simply closer to his camp. Caesar describes this deployment as an iniquis locis for his army. The adjective iniquus usually means unbalanced or unfair, adverse or disadvantageous, but its first meaning is simply uneven or not level -- as in uneven ground. Locus is simple place or location.

An Alternative Disposition

On the final day Pompey rested his right flank on the creek bed, but there is no indication that he did so on other days. If the camp location preferred by Morgan is correct, then there may be another way for Pompey's army to have used the high ground to advantage.

In this illustration Pompey has arranged his men along the high ground to the north of the open plain. His entire army enjoys the advantage of height. Caesar's army would also have to execute an awkward turning maneuver to accept battle.

This would more closely match the disadvantages of position referred to in the narrative.

On the day of the battle Pompey arranged all of his cavalry on his left flank. If he used a wholly different location on the previous days there is no compelling reason he would have done the same thing. In this illustration both armies are shown with their cavalry and skirmishers evenly divided between both flanks.

A Different Site for the Battle

Morgan follows Lucas, T. Rice Holmes, Postgate and Veith in preferring the north bank of the Enipeus river for the site of the battle. Only older authors appear to have favored sites on the south bank and these men were successful in showing that those sites did not fit the known facts of the battle. The other 4 men, however, would site Pompey's camp on the flanks of Mt. Dogantzis, the peak to the west of the plain. In that case the battle would have occurred at the narrow end of the plain.

If this were the location for the camps then the early positions of Pompey's army are obvious. The lower slopes of Mt. Dogantzis give a clear advantage and would perfectly fit Caesar's description. If this were the site then the actual battle would have been fought someplace between the two armies as they appear on the right -- probably just west of the small hill on Caesar's right flank..

Morgan argues against this site because there is no hill nearby to which Pompey's infantry could have fled and which would have been small enough for Caesar to have surrounded with entrenchment's in an afternoon. The obvious choice for this hill, virtually the only choice, would be Mt. Dogantzis itself and it is far too big for Caesar to have even contemplated encirclement. There is also no clear path for the infantry to retreat in the direction of Larissa.

Also arguing against this location is the narrowness of the plain at that end. The armies illustrated have the Delbruck cavalry numbers; that is, Pompey is shown with less than half the cavalry Caesar claimed for him. Even with this reduced number, there is almost no room for them to maneuver. Caesar's army, in the location shown, is even more confined, though with a smaller cavalry force this may have actually been to his advantage.

The models will follow Morgan's choice for camp and battle sites. The alternative site is shown to illustrate some of the difficulties one faces in trying to understand Pharsalus.

Deployment on the Day of Battle

The illustration below follows Morgan in siting the battle. The armies have the river on one flank and all of their cavalry on the other.

The illustration above shows Pompey's cavalry at about 3,000, following Delbruck (See "The Battle of Pharsalus: The Two Armies" for the discussion of the size of the two armies.

Why not a Very Wide Formation?

Pompey is said to have had 7,000 cavalry. Even though this number is regarded as suspect, what it it were correct. In that case Pompey's army would resemble the illustration below, with a much greater cavalry force.

The really interesting question is why wouldn't Pompey, or any general for that matter, spread out his superior force to completly outflank the enemy. The illustration below shows how this might have looked.

Pompey could have spread out his cavalry all the way to the hills and still have matched Caesar's formation depths. In addition, Pompey's cavalry could have been reinforced by the light infantry (the two shorter lines behind the long cavalry line) at the point where they would encounter Caesar's forces.

Most of Pompey's cavalry could simply have ridden unopposed around Caesar's flank and attacked the rear of the army, a guaranteed way to achieve a victory.

Again, assuming for the sake of the example that Pompey actually had 7,000 cavalry, the interesting question is just why he didn't adopt a formation like this one.

The answer may lie in questions of command and control. Once the army deployed it was virtually impossible for the commanding general to control remote units. Visibility was poor. Information had to be exchanged by sending riders back and forth; a difficult, slow and uncertain method of communication.

If the formation on the left were adopted the furthest units would be some 8,900 feet from the nearest infantry cohorts. That is almost 3,000 yards.

The "Introduction to a New Model" page discussed distances. A short section from that page is repeated here for convenience.

The following drawings accurately illustrate what detail can be seen at various distances.


For an approximately accurate perspective view hold a ruler at arms length and position yourself so that the black T under the words "50 Yards" looks like it is 1 inch high. At 1,700 yards very little could be seen. Large Roman armies, such as those used during the civil wars, could number 10 or more legions. Such an army would have a front of around 3,000 yards, twice the distance shown in the chart above. At that distance men and horses would be mere specks.

The chart makes it clear that at distances greater than 300 yards it would be virtually impossible to distinguish friend from foe -- on a clear day.. Add in dust, the lack of high ground from which to get a view and the rapid movements of cavalry action and the problem become even worse.

A very wide formation such as is illustrated above would be unmanageable. The individual units would no know what was happening anywhere other than in their immediate vicinity. Because of the great distances they would be wholly beyond the control of any senior officers. It would be impossible to direct or coordinate their activities. In essence, the formation would simply be a large number of completely uncoordinate small units each doing what it saw fit.

All very large armies would have this difficulty, whether they were comprised of infantry or cavalry units. Perhaps the difficulties of command and control help explain why so many smaller armies were successful against more numerous enemies. A small coehesive and disciplined army is superior to a large number of unorganized men.

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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.