Pompey the Great and the Campaign
of 49 B.C.:
Analysis of a Military Blunder
Albert A. Nofi
The innovative analytic
techniques which gave birth to modern wargaming – systems analysis, operations
research, simulation modeling – have been extensively applied to the examination
of modern – and future – warfare.
They have been less widely applied to the study of earlier conflicts.
Most existing efforts to use such techniques in the study of warfare in
the ancient period have been interesting but limited due to their commercial
nature. Attempts to embark upon
more serious, scholarly undertakings have not been successful, due partially to
a shortage of personnel trained in both the classics and simulation design and
partially to a lack of academic interest. Nevertheless
there are innumerable military events in the pre-modern age which lend
themselves readily to serious examination using these techniques.
One of the best examples is the campaign between C. Julius Caesar and Gn.
Pompeius Magnus in Italy in 49 B.C., for such an analysis rather clearly
demonstrates that Pompey the Great committed a
grave strategic blunder.
In 60 B.C. Gaius Julius Caesar,
Gnaeus Pompeius Magnus, and M. Licinius Crassus had formed a consortium for the
purpose of plundering the state, a cabal known to history as the "First
Triumvirate." They were rather
successful in this conspiracy, seizing high office and assigning each other
various lucrative provincial commands. But
as time passed, the arrangement began to deteriorate.
Caesar's daughter Julia, who had been given in marriage to the
considerably older Pompey, died in 54 B.C.
Crassus met his end on campaign against Parthia in 53 B.C.
By 50 B.C. Pompey had been won over to the party of the establishment,
which feared Caesar as a champion of the increasingly restive citizenry.
Tension between the two grew and war soon became more or less inevitable.
At the time, late 50 B.C. by
modern reckoning, the Republic appears to have had between 21 and 23 legions
under arms. These were deployed
primarily on the fringes of Roman territory.
Legionary Postings, Late 50 B.C.
|A. Although Pompey was
titular commander, in his absence command was being exercised by three
legions stationed in Gallia Cisalpina, by excluding 22 cohorts of newly
recruited manpower not yet organized into legions, some of which would go to
form Caesar's famed Alaudae, Gallic-speaking
|C. These included Pompey's
old 1st, from his consular series raised in 52 B.C., which had been lent
to Caesar for the Gallic Campaign of 52-51 B.C., and Caesar's old 15th,
which he had raised in 53 B.C. In early 50 B.C. a decree of the Senate
had forced Caesar to turned both legions over to Pompey in anticipation of
the latter’s planned Parthian Campaign.
|D. According to Cicero,
two legions were so under strength as to be the equivalent of but one
regularly constituted legion.
|E. Two of these legions
were certainly recruited from the remnants of the six legions lost by
Crassus in 54 B.C. The evidence for the other two is less
Matters came to a head very early
in 49 B.C., when the Senate effectively declared Caesar an outlaw.
On 11 January 49 B.C. Caesar led his army across the Rubicon, a little
river in northeastern Italy which marked the boundary of his provinces.
Caesar’s invasion of Italy
presented Pompey with two options:
1. Stay and fight.
If Pompey chose to stay and
fight, he would face an immediate clash of arms with the aggressive Caesar.
However, although he was arguably as good a commander as Caesar was, he
had not taken the field for many years. Moreover,
he had only two seasoned legions, both of which had recently been in Caesar's
service, and was trying to raise at seven new legions with which to face the
Caesar was coming south with at least three, probably six, and possibly
ten veteran legions, plus at least two legions of recruits.
Moreover, the situation deteriorated very rapidly.
So swift was Caesar’s advance, that four of the seven legions which
Pompey was attempting to raise soon fell under Caesar’s control.
In short, the concentration of forces against him was something between
30 and 130 to 35, based on the relative "raw combat power" of the
This estimate is loosely based on an application of
the late Trevor N. Dupuy’s "Quantified Judgment Method."
Military organization, equipment, and doctrine were identical on both
sides, which greatly simplifies such calculations.
Legions in this period generally numbered approximately 4,500 men.
If we assume that a veteran legion has a strength of 10, we can use
Caesar’s own estimate that veteran troops were about twice as effective as
recruits, to set the value of green legions at 5.
Possible Pompeian Outcomes
Hypothetical Italian Campaign in 49 B.C.
In fact, the best case
situation was that which actually occurred.
Caesar invaded Italy with his three veteran legions, plus two-legion equivalents
of recruits, and supplemented his army with four of the legions
Pompey had been trying to raise, giving him a nearly two-to-one edge in manpower
over his rival. These were not
particularly good odds. All other
things being equal, Pompey could hope for no more than a drawn battle, and there
was a very strong likelihood that he might suffer a disastrous defeat.
In consequence, flight was Pompey’s only practical alternative.
And so he pulled his forces into the port of Brundisum while Caesar
overran most of Italy without a fight.
Of course flight had its
drawbacks. In taking flight, Pompey
would inevitably suffer a loss of prestige and, worse, the loss of the enormous
human and financial resources of Italy.
In terms of manpower, during the
first year of the civil war, Caesar would raise about 14 legions in Italy,
including the four taken from Pompey. Between
the end of 49 B.C. and his death, in March of 44, Caesar would raise a further
20 or so legions in Italy, for an annual average of four or five legions.
Thus, Caesar would put a minimum of 155,000 men under arms in Italy over
five years, out of a citizen population of perhaps 1,150,000 men.
By abandoning Italy Pompey also
left Caesar a considerable financial windfall.
Although Italy, only lightly taxed, contributed but 30 million sestertii
to annual state revenues, estimated at some 350 million, there was a vast
amount of the Republic’s treasure on deposit in Rome, primarily in various
The precise figure cannot be estimated with any degree of accuracy.
In 88 B.C. Sulla had obtained 37.8 million sestertii from the
various state treasuries in order to finance his campaign in the Orient.
Despite this, there remained enough left for the younger Marius to make
off with an additional 60 million sestertii in 83 B.C.
Caesar appears to have done at least as well.
In the first weeks of his invasion of Italy he raided the state
treasuries, making off with enormous sums.
Indeed, so flushed was Caesar's war chest that he returned 6 million sestertii
seized from Pompey’s legate Domitius Ahenobarbus at Corfinum in the first
weeks of the war.
Naturally, these enormous
resources of men and treasure would have been of great value to Pompey's cause.
Nevertheless, if his cause was to have any hope of prevailing, Pompey had
no choice but to flee.
Moreover, he could do in safety, for he had control of the
seas. Within months of the
outbreak of the civil war he had managed to concentrate some 600 ships,
including at least 300 triremes.
In contrast, the best Caesar was “destitute of ships,” being able to
muster only about 150 vessels of various types.
determined, on the basis of the military situation, that flight was the best
course of action, Pompey was now confronted with three possible directions in
which to flee. These were:
A). To Africa,
B). To Spain,
C). To Greece.
The African Option. Flight
to Africa was an attractive possibility.
The province was just a few day's sail from Italy, which would permit him to
pose a constant threat to Caesar's base.
In addition, Africa's location could be of great value in developing alternative
strategies due to its central position, through the use of his naval
supremacy. Militarily the province also
offered several advantages. Roman – and
romanized – manpower resources were considerable, so that Pompey's supporters
would activate between eight and ten legions there within two years, albeit that
not all were at 4,500 men.
Africa offered yet another
advantage, for that Pompey had an ally there in the person of King Juba I of
Numidia. Though not necessarily
completely trustworthy, Juba had reorganized his army along Roman lines, and
possessed bring four legions plus a sizeable contingent of light troops, a
numerous force of cavalry, and many elephants which would be at Pompey's
Finally, Africa had substantial
financial resources. Its annual
contribution to the state revenues has been estimated at some 8.6% of the total,
about 30 million sestertiii, a tax yield equal to that of Italy itself.
The Spanish Option.
If Pompey chose to flee to Spain he would also find many
advantages. He was technically
proconsul of the Spanish provinces, had campaigned there for several years in
the past, and had the favor of the populace, both Roman and native.
From Spain, Pompey would be able to threaten Caesar's recent conquests in
Gaul, and possibly fall upon Italy from the Alps, for he had strong allies in
the romanized southern portions of Gaul, where the city of Massilia had declared
for him against Caesar.
More importantly, there were six
seasoned legions in Spain plus many auxiliary troops, all under commanders loyal
In addition, thee was sufficient Roman and Romanized manpower in Spain to
eventually permit the raising of about a dozen additional legions over the next
Finally, Spanish financial
resources were considerable. The
two provinces normally produced an annual contribution of about 8.0% of the
state's revenues, some 28 million sestertii, and were so wealthy they
could readily be squeezed for more.
The Greek Option.
Choosing to go eastwards, to Greece, also offered a
number of advantages, not least because Greece controlled access to the wealthy
provinces of Asia and Syria. Geographically,
Italy was but a day's sail from Greece, so Pompey would be in a good position to
threaten Caesar's control of the peninsula.
Politically, Greece and the Orient were familiar territories to Pompey,
for he had extensive campaigning experience there, and was quite popular in some
There were some military
resources in these areas, with two seasoned, albeit under strength, legions in
Cilicia, and four more in Syria.
However, the pool of additional manpower was poor.
By concentrating all available forces, scraping the bottom of the barrel
for Roman and Romanized manpower, by calling up discharged veterans, and by
enrolling legally unqualified personnel, the best that could be done by early 48
B.C. was to effect a net gain of two new legions, bring the existing ones up to
full strength, and concentrate a substantial force of cavalry and light
infantry, leaving Pompey with just eleven legions.
But if the Eastern provinces were
poor in manpower, they were immensely wealthy in treasure..
Taken together, they generated about 51.4% of state revenues,
some 180 million sestertii.
So Pompey would not want for money.
Thus, each of the choices open to
Pompey had particular advantages. A
comparison of the differences among these may be useful at this point.
Comparison of Strategic
. Strategically, each of Pompey’s three options offered certain advantages
Strategically, Africa was
probably the optimal choice. From
Africa, Pompey would not only be able to pose a direct threat to Italy by sea,
but also would be able to shift forces easily in any direction to counter any
possible move by Caesar or for his own purposes.
He would, of have to pay the political price of relying heavily on a
non-Roman ally, but once Caesar had been taken care of Pompey would be able to
cope with Juba of Numidia at his leisure.
Greece put Pompey in a position
to pose the most direct and immediate threat to Caesar's base in Italy.
But he would be poorly placed to counter Caesar's activities in the West;
Should Caesar strike at Spain or Africa, Pompey would find it difficult to
respond from Greece, save by direct attack on Italy.
From Spain, Pompey would be less
able to threaten Italy directly, and unable to intervene quickly in Greece or
even Africa, but would be in an
excellent position to threaten Gaul, and thence advance overland into Italy.
Moreover, given Pompey's naval supremacy, Spain could still be useful for
operations oversea against Italy.
Comparison of Operational
Consequences . There exist significant differences in the operational
military consequences of each of the options. These may best be examined
in the form of a tabular presentation.
Projected Alternative Military Situations
the number of legions which would have been available in the theater assuming
a decision was reached din 48, as was the case in Greece, including the five
which Pompey would have brought with him from Italy and those which Caesar
would have had available.|
C.P. is the estimated combat power of these legions, assuming
veteran ones at 10, recruit ones at 5, and Numidian ones at 7.
P:C Ratio is the balance of forces between Pompey and Caesar, in
both legions and combat power.
Outcomes are based on the Imperium Romanum II combat results system.
By taking refuge in Spain, Pompey would have enjoyed
an immediate, and perhaps decisive military advantage. Africa would
likewise offer important military advantages. However, the military consequences
of a retirement to the Eastern provinces, would be clearly unfavorable,
particularly since Caesar would be able to concentrate the bulk of his veteran
forces in that theater.
Consequences Financial of
Comparison. Regardless of the theater to which
Pompey chose to retire to order to rebuild his fortunes, his financial situation
would not have changed significantly, since he would retain political control of
the other areas. Similarly, Caesar would
retain control of various areas as well.
Thus, the fiscal strength of each side would remain essentially unchanged
whichever option Pompey chose.
The provinces which were controlled by Pompey, Macedonia, Greece, Crete, Asia,
Bithynia, Pontus, Cilicia, Cyprus, Syria, Cyrenaica, Africa, and the Spain's,
yielded the bulk of the Republic’s tax revenues, some 238 million
sestertii, about 68% of annual state income. In contrast, Gaul, Cisalpina, and Italy itself, plus
Sicily, Sardinia, and Corsica, controlled by Caesar, yielded revenues of 112 million
sestertii, only about 32% of annual state income.
To be sure there would be some
difficulty in transferring funds from theater to theater, but Pompey's control
of the seas was undisputed. So
financially resources, Pompey was comfortably well off regardless of which
theater he chose to retire to. Indeed,
arguably, had he chosen to take refuge in Spain or Africa, he might readily have
used his fleet to interfere with Caesar’s ability to gain financial benefit from Sardinia, Corsica, and Sicily, 30 million sestertii annually. As the costs of operating an army were enormous, such a blow would Caesar
a lot more than it would have helped Pompey.
Operating a single 4,500-man
legion for a year ran to some 4 million sestertii.
Thus, the revenues of the provinces which Pompey controlled would have
been sufficient to maintain under arms nearly 60 legions, a number which would
have pressed the limits of the manpower resources of the Roman state.
In fact, Pompey's faction never mustered more than 23 legions at any one
time, peak strength being reached during the early months of 48 B.C.
As a result, his enormous revenues were more than sufficient to his
needs. On the other hand, Caesar's
ordinary revenues were rather tight, being sufficient to maintain only 28
legions on active service. From 49
B.C. through 46 B.C. Caesar actually averaged about 29 legions under arms at any
given time, though his peak strength gradually rose to 36.
To be sure, in this same period he added considerably to his revenues, by
acquiring control of the Spain's and the Orient from the Senatorial party, as
well as through confiscations. But
his expenditures were enormous as well. At
the onset of the civil war he had promised a rather lavish donative to his
troops, amounting to about 102.9 million sestertii per legion, thereby
incurring an obligation to pay over 3.7 billion sestertii at the
end of the civil war, a sum equal to about 1060% of the total annual state
Given its strategic and military advantages, Spain was Pompey's optimal
objective upon retiring from Italy in early 49 B.C.
Failing Spain, Africa offered significant advantages.
The least desirable area to which he could withdraw was Greece and the
Oriental provinces, for, while enormously wealthy, they offered little in the
way of military resources.
In the event, Pompey chose precisely the worst option.
On 17 March 49 B.C., Pompey took ship for Macedonia.
The consequences were fatal to
Pompey's decision in this
instance has not hitherto been questioned.
Lawrence Keppie calls the retirement "sensible on strategic
grounds,” while Robin Seager states flatly that "[Pompey] intended to use
the resources of the East to blockade and if need be to reconquer Italy,” and
F.E. Adcock goes so far as to say, ". . . Pompey adopted the course which
gave the most chances."
Even Hans Delbruck, the inventor of modern military analysis, overlooked
Pompey's poor judgment in this matter, for he merely made some general remarks
about the hopelessness of the situation in Italy, concluding with an almost
casual mention that Pompey retired to Greece, before hurrying on to an analysis
of Caesar's Spanish Campaign.
Nevertheless, it is difficult to escape the conclusion that
Pompey made a serious error of judgment. Indeed,
Caesar himself is reported to have been "astonished" by Pompey's
He clearly understood the implications of Pompey's actions.
Resisting the temptation to pursue his foe immediately, Caesar set out
instead for Spain, saying "I am off to meet an army without a general; when
I return, I shall meet a general without an army."
Which is precisely what he did.
The causes of
the bout of civil disorders and wars which plagued the Roman Republic in its
last century have been rehearsed many times, usually in terms of modern
socio-political notions – such as Marxism – which lack validity when
applied to a near-subsistence society over 2,000 years in the past.
Put most simply, it came down to a failure on the part of the Roman
elite to adequately understand that the existing political and military
institutions of the state were leading to the disenfranchisement and
impoverishment of the yeoman peasantry, on which the strength of the state
lay. On this, see
P.A. Brunt, Italian Manpower, 225 B.C.-A.D. 14 (Oxford: 1971),
Compiled from Caesar,
B.C, i, 38; iii, 4; Caesar, B.G., viii, 46, 54; Cicero, ad
Fam., XV, 4, 3.
viii, 54, and B.C., i, 9.
Fam., XV, 4, 3
For a fairly
even handed contemporary summary of the events immediately preceding the
crossing of the Rubicon see Suetonius, Div. Iul., 29-32
peculiarities of the Roman calendar were such that the date was out of
synchronization with the seasons by about ten weeks.
As a result although 11 January was the legal date, it was actually
about 19 October of 50 B.C. In
46 B.C. Caesar would institute a calendar reform which set matters aright,
but resulted in that year having fifteen months.
Caesar, B.G., vii, 54, and B.C., i, 9; Appian, B.C., II,
actually raised about seven legions of recruits, but so rapid was Caesar's
advance that four of these fell under the latter's control; Cf., Caesar,
B.G., i, 25; Plutarch, Cae, xxxv, 1, and Pomp., lx, 4;
Velleius, II, xl, 1.
outcomes shown in the table are based on the standard combat results table
used in this writer’s Imperium Romanum II (New York: 1989), which
was derived from an analysis of the outcomes of several dozen battles.
It is assumed that, having the stronger forces, Caesar was most
likely to do the attacking, which was quite normal for him in any case.
assume legions at 4,500 men each, generally regarded as the norm for the
period, and exclude men serving afloat and as auxiliaries.
For population figures see Livy, xlviii & xcvii, recording the
census of 70-69 B.C., as modified by the calculations in Brunt, pp. 90-99,
who makes the reasonable assumption that about 150,000 of the 1,150,000
adult male citizens were abroad. Note
that the legionary manpower raised by Caesar in Italy was some 20% greater
than that which Pompey had senatorial authorization to levy at the onset of
the civil war, as noted in Appian, B.C., II, 34.
The total number of legionaries raised in Italy during 49-44 B.C.
amounted to perhaps as many as
175,000 men, including the three recruit legions which remained with Pompey.
Considering the number of men raised for the fleet and to serve as
officers with auxiliaries, the total number recruited in the period must
have been at least 200,000. Add
to this figure the 80,000 already under arms at the end of 50 B.C. and the
manpower drain of this bout of civil wars amounted to 280,000 men, or about
24.4% of total male citizenry; Cf.,
Brunt, p. 511.
This calculation is based on Plutarch, Pomp., 45, and Tenney Frank, An
Economic History of Rome (Baltimore: 1920), pp. 136ff.
22. If one thinks of sestertii
as dollars, and adds a zero, some notion of the magnitude of the sums involved
will become clear.
Maximus, 7, 6.4; Pliny, Hist. Nat., 33, 16.
B.C., II, 49 & 87; Caesar, B.C., iii, 3, 5 & 3, 27;
Cicero, ad Att., IX, 9, 2; and Plutarch, Pomp., lxiv, 2, which
gives him but 500 warships.
xxxv, 3; Appian, B.C., II, 41 & 49: Caesar, B.C., i, 36,
II, xiv, 96; Caesar, B. Afr., 1; Caesar, B. Alex., xxxiv, 5;
Caesar, B.C., ii, 23.
Caesar, B. Alex., xxxiv, 5.
Plutarch, Pomp., 45.
xviii-xxi; Plutarch, Sert., xviiiff; Caesar, B.C., 29.
Caesar, B.C., i, 34-36, & ii, 1-22; Florus, II, xiii, 23;
Velleius, II, xl, 3.
The Massiliots, clients of the Domitii Ahenobarbi, solidly Pompeian
supporters, were ultimately besieged by three of the legions Caesar had co-opted
from Pompey in the first weeks of the war.
i, 38. There was also one
legion composed of locally recruited non-Romanized personnel.
Caesar, B.H., 7; Cicero, ad Att., v, 18.2.
One of these legions was eventually recruited from non-Romanized
personnel, bringing the total of “vernacular” legions in Spain to two.
extensive ancient account of Pompey's activities in the Orient may be found
in Appian's B.M., which may be supplemented by Plutarch's Pomp.,
xxx-xlii; Velleius, II, xxxiii, 1-4, xxxvii, 1-5, & xl, 1-3.
For a modern synthesis, see Robin Seager, Pompey (Oxford:
1979), pp. 28-55.
36; Cicero, ad Fam., XV, 4, 3; Caesar, B.C., iii, 4.
iii, 4 & 88. Most
importantly, and see Hans Delbruck, History
of the Art of War within the Framework of Political History, Vol. I, Antiquity
(Westport, Ct: 1975), pp 542-555, for a critical examination of Caesar's
tally of Pompey’s manpower, with particular concern for the actual numbers
based Plutarch Pomp., 45, and Frank, pp. 136ff.
Note that these figures exclude monies derived from plunder, expropriation,
loans, and extraordinary levies. The
sums involved could be enormous. In
49 B.C., Pompey's legate Varro secured 28 million sestertii by an
extraordinary levy on Roman citizens resident in Spain, about equal to the
annual provincial contribution to the treasury (Caesar, B.C., ii,
18). In 43-42 B.C., Cassius
secured 32.5 million sestertii when he captured Rhodes (Appian, B.C.,
IV, 73; Dio Cassius, 47, 33.4; Plutarch, Brut., 37) and a further
37.5 million from Tarsus (Appian, B.C., IV, 64; Dio Cassius, 47, 26.2
& 31.3). Even a minor
campaign against some insignificant insurgent hill tribes could yield
considerable boodle, such as the 12.5 million sestertii which Cicero
captured while governor of Cilicia in 51 B.C. (Cicero, ad. Att., V,
20, 5), a sum greater than the annual provincial
Pis., 86; Plutarch, Cae., 28 & Pomp., 55.
Supporting this is Cicero's comment that the two under strength legions he controlled in Cilicia in 51 B.C. each cost about 3
million sestertii in pay and maintenance a year (Cicero, ad Fam., V ,
20, 9, & ad Att., V, 11, 5), which was about 60% of the annual
revenues of the province (Cf., Frank, pp. 136ff).
This would today easily be in excess of 37 billion dollars. Appian,
B.C., II, 102; Dio Cassius, 43,21; Seutonius, Div. Iul., 26,
Note that these figures include only monies promised to
ordinary soldiers (20,000 sestertii each), centurions (40,000), and
military tribunes (80,000). Benefits
to higher ranking personnel were on a similarly generous scale.
Of course Caesar did not seem to have worried overmuch about
money, for if he should lose he would be dead, while if he won he would have
the whole empire to plunder.
Att., IX, 15.6. In terms of
the Julian calendar this was actually 23 December, 50 B.C.
The Making of the Roman Imperial Army (Totowa, N.J.: 1984),
pp., 104-105; Seager, p. 175; F.E. Adcock, "The
Civil War," The Cambridge Ancient History, The Last Age of
the Roman Republic, (Cambridge:
1966), p. 645.
Delbruck, I, 515-516.