Battle of Sellasia by Igor Dzis

No preparation for attack or defence had been omitted;
but everything was in order, either for offering battle with effect, or for
holding an almost unassailable position.

Polybios, 2.65

The Campaign

Invading the Peloponnesian stronghold of a wearied and weakening
Kleomenes in 224 BC, Antigonos attempted to shore up his position by
immediately bringing the Spartan king to battle. Although battered and
perpetually in need of funds, Kleomenes was not yet beaten and it was only
after almost two years of manoeuvring, pillaging and siege warfare that
Antigonos finally began to hem in his flagging opponent. Ultimately, it was the
brutal pragmatism of Kleomenes’ financier, Ptolemy III, which brought the
Spartan king to battle. Informed that his Egyptian subsidies had been withdrawn
in the face of the virtual unification of Greece and Macedon against Sparta,
Kleomenes realized he could no longer afford to avoid a fight. Changing his
strategic outlook entirely, the wily campaigner, who was not about to go down
without a struggle, began making immediate preparations for the coming
conflict.

Withdrawing to the rugged hills guarding the Lakonian
heartland, Kleomenes set about hurriedly fortifying the passes through which
Antigonos would likely advance. While these preparations were underway, the
Macedonian king eagerly gathered together his army to take up the challenge for
which he had been yearning. By July 222, Antigonos and his men had arrived near
the city of Sellasia, which sat astride the main route to Sparta, less than a
day’s march from the capital. There Kleomenes waited with a veteran army in a
strong position from which the Spartan king would not easily be driven.

Despite his comfortable numerical advantage, Antigonos was
nevertheless daunted by the strength of the enemy deployment and hoped to find
a way to avoid storming the strongly-held heights. Encamping his men nearby,
the Macedonian king dispatched scouts to search for a weakness in Kleomenes’
position. While this was going on, he also attempted to lure the Spartan into
surrendering the heights willingly through aggressive manoeuvring, feigned
assaults and flanking movements. To Antigonos’ chagrin, Kleomenes could not be
bullied into abandoning his position and after days of futile efforts,
Antigonos’ supplies began to run low. Realizing that Kleomenes would only
vacate the hills if he were forced to do so, Antigonos ultimately resolved to
risk assailing the heights before his multinational army began to grumble over their
empty stomachs.

The Battlefield

In defending the mountain passes surrounding Lakonia,
Kleomenes, like the Greeks at Chaironeia, sought to make use of a naturally
strong chokepoint. This he found slightly to the north of Sparta near the city
of Sellasia, where the Oinous River ran between two prominent hills on its way
toward the great Eurotas. As the main north-south route to Sparta, this valley
was crucially important to the defence of Lakonia and was the perfect place for
an outnumbered and outmatched defender to occupy.

Concentrating his forces across the road, Kleomenes anchored
the flanks of his army on two sparsely-wooded hills. The westernmost was called
Euas and around its flank a small seasonal river known as the Gorgylos often
flowed, however in July 222 the summer heat had caused the stream to run dry.
Across the battlefield the larger, easternmost hill sported the appropriately
majestic name of Olympos. Kleomenes linked these two positions by occupying
both sides of the intervening valley, which was roughly bisected by the Oinous
River. This deployment placed him in a very strong position with his flanks
firmly anchored on the hills while the centre of his line was held slightly
back in the narrowest part of the pass. This not only provided the king with an
aggressive and difficult-to-attack position, with which Polybios was much
impressed, but would also allow his right and left wings to easily outflank any
attack on his centre.

To secure his flanks, Kleomenes relied not only on the slope
of the hills, which was severe on Euas and somewhat less so on Olympos, but
also on the labour of his men, who were ordered to dig trenches and erect
palisades on both hillsides. The king’s position was further secured by the
fact that rough ground radiated outwards from the sides of both hills, making
large-scale flanking movements difficult.

Leaders and Armies

Part of the reason for Kleomenes’ selection of such a
formidable defensive position was that his army, though a veteran force and a
proven match for the Achaians, could not compete numerically or qualitatively
with the army of Antigonos. By entrenching his men along a series of hills
across the road to Sparta, Kleomenes gave them a far better chance of being
able to resist the Macedonian king’s aggressive drive on the capital. His
judicious deployment along these hills, however, would prove just as important
as his selection of terrain.

Confident in the security afforded by the steep slopes of
Euas, Kleomenes stationed his left flank composed of perioikoi (Lakonians who
were not full Spartan citizens) and allies under the command of his brother,
Eukleidas, atop this smaller prominence. Lightly-armed though these troops
were, the Spartan king was justly confident in their ability to defend the
fieldworks at the summit of the steep hill. Occupying the valley to the east of
Euas, Kleomenes posted an unknown number of cavalry, almost certainly fewer
than Antigonos, as well as a contingent of mercenaries. Across the battlefield,
Kleomenes himself occupied the gentle slopes of Olympos with a phalanx of 6,000
Spartans armed in the Macedonian fashion and screened by some 5,000 light
infantry. Behind their fortifications at the summit of each hill, Kleomenes’
troops felt well prepared to resist a much larger force than that which
Antigonos brought with him.

As he considered how best to attack the enemy, Antigonos
knew that to break through his foe’s expertly-positioned formations would
require not simply the use of masterful tactics, but also no small amount of
luck. Fortunately for Antigonos, his army consisted of some of the finest
soldiers of the day drawn from many different military traditions. In all, his
infantry units amounted to around 28,000 troops and were comprised of heavy,
light and missile soldiers. Some 10,000 of these men were Macedonian
phalangites, whose number included an elite unit known as the Bronze Shields,
while the rest were mostly light infantry mercenaries or Antigonos’ Greek
allies.

As dynamic as his army was, Antigonos’ force still serves to
illustrate the general ongoing trend towards a decline in the importance of
cavalry. With almost 30,000 infantry under his command at Sellasia, Antigonos
deployed a mere 1,200 cavalry.

Deploying his forces to effectively counter the arrangements
of the Spartan king, Antigonos himself took up position opposite Kleomenes near
the foot of Olympos. There he stationed a large portion of his Macedonian
phalangites in a phalanx of double the normal depth. Nearly 5,000 of Antigonos’
light-armed mercenaries were preceding and screening these troops. His centre
occupied the valley below and was composed of his cavalry supported by 2,000
allied infantry. His right wing held the crucial position opposite Euas and
would lead the army’s attack. There Antigonos placed the remainder of his
phalanx, the Bronze Shields, to lead the attack up the hillside. Though the
sources are not entirely clear, it seems that Antigonos dealt with the problem
that Euas’ slope presented to the formation of his phalanx in an innovative, if
not entirely original, way. Perhaps influenced by stories of Pyrrhos’
deployment at Asculum or by the commentaries of the Epeirot king himself,
Antigonos interspersed companies of Illyrian infantry between the units of his
phalanx in order to give the overall formation a greater flexibility to cope
with the rough terrain. Behind these forces the king drew up the light and
versatile Akarnanian infantry and his Cretan mercenaries, most likely bowmen,
while a reserve force of 2,000 Achaian infantry was positioned still further to
the rear.

With his forces poised to attack and his supplies running
low, Antigonos realized that he would have to act soon or risk the
disintegration of his army. As night fell yet again on his encampments below
the commanding heights near Sellasia, the king reflected on his risky plan and
called his officers to his tent to discuss their plan of attack for the next
morning.

The Battle

As the morning sun broke over the horizon and began to warm
the grim hills near Sellasia, Antigonos Doson, king of Macedonia, decided that
the time had finally come to launch his assault. Nodding curtly to his aide,
the king watched as the officer turned toward the western end of the quiet
battlefield and hoisted a large linen flag into the sky. There in the distance
the king’s right wing sat brooding near the base of Euas. As the officer swung
the flag back and forth, however, a perceptible flurry of activity could be
faintly seen. After a few moments, Antigonos’ right wing began to slowly lumber
toward the rugged hill to their front. Kleomenes, who was then talking with a
group of his officers at his commanding position on top of Olympos, immediately
noticed the movement and sent word to his men to make ready. Watching the
slowly advancing enemy below, Kleomenes had no way of knowing that a far more
serious threat was preparing to strike just off his left flank.

Unbeknownst to either Kleomenes or his brother Eukleidas,
during the night a large force of Illyrian and Akarnanian infantry had crept
around the foot of Euas and occupied a portion of the dry Gorgylos streambed.
From on top of Olympos, Kleomenes is said to have noticed fewer troops in the
enemy right wing and given orders to discover their whereabouts, but as
Antigonos’ army now began a general advance across its entire front, Kleomenes’
officers advised the king to focus instead on the enemy before him. The Spartan
monarch grudgingly agreed and set about preparing his men for the coming
struggle. Across the field, the officers of Antigonos’ flankers spoke a few
final words of encouragement to their men before drawing their swords and
ordering the assault.

Having lain concealed throughout the night, these troops now
sprung up from their hidden positions and with a shout began to dash boldly up
the hillside. Intently observing the slow approach of Antigonos’ right wing to
his front, Eukleidas was startled by the commotion and the accompanying shouts
of the men off to his left. Galloping over to that flank, the bewildered
commander arrived just in time to witness the sudden and dramatic emergence of
the enemy. Though Kleomenes had ordered that the hills should be fortified with
ditches and palisades, Eukleidas had not extended his defences for any
appreciable distance along this flank. The dumbfounded Spartan simply had not
considered that the enemy might move into position to assail this unfortified
flank without being noticed. A situation that had seemed well in hand a moment
before was now reeling dangerously out of control.

 Across the field
Antigonos silently watched the awe-inspiring spectacle of his entire army in
motion with trepidation, for just as crucial as his right wing, which was now
nearing the base of Euas, were his centre and left. Both advanced toward the
enemy at a slow and menacing pace; Antigonos’ plan required that he pin down
the bulk of Kleomenes’ army with his centre and left while his right closed in
for the first decisive manoeuvre of the battle. With the Macedonian king’s men
pressing dangerously near all along his line, Kleomenes could send no aid to
Eukleidas, whose troops on Euas would be forced to face Antigonos’ wrath on
their own. For this plan to succeed, however, the Macedonian king would have to
do his utmost to restrain the battle-ready soldiers of his left and centre from
engaging before he gave the signal.

Having reached the base of Euas, Antigonos’ articulated
phalanx of Macedonians and Illyrians now began the gruelling work of moving up
the rugged slopes. Once the punishing ascent began, it became readily apparent to
all that the king’s thoughtful modification to his force was proving its worth.
Slowly churning its way up the hillside, individual units of the phalanx at
times lagged behind or jutted ahead as they struggled with rougher terrain or
denser ground cover than others, but despite all this the line never broke or
became seriously disordered. Due to their less-rigid unit structure, the
Illyrians were able to lend the phalanx a flexibility that allowed the
phalangites to concentrate on keeping only their own unit together, rather than
worrying about maintaining the rigidity of the entire formation. The men of
Antigonos’ phalanx trudged ever higher up the steep gradient, advancing
steadily toward the dark line of enemy soldiers manning the palisades near the
hill’s summit; tiring by the minute but driven relentlessly on by their
officers. Though these men could be the bane of a soldier’s existence, they
were also their best bet for success and frequently some of the bravest troops
on the battlefield. During the ascent of Euas, Antigonos’ phalanx officers
strode back and forth barking orders, shouting encouragement and ensuring the
line was properly maintained. It was not just the officers who urged the
soldiers on, however, as the echoing cries of the flankers now rang out from
the right side of the hill.

Clawing their way up the flank of the hill, the Illyrians
and Akarnanians approached a hastily-assembled Spartan flank guard consisting
of light infantry and missile troops. As they drew near, arrows, javelins and
sling stones scythed into their ranks with terrible effect, but still they
pressed on with the attack. Assaulting an elevated position on the run with
little more than javelins and rocks, Antigonos’ men could not have inflicted
any serious damage before colliding with the enemy. As the unarmoured troops
drew off to continue showering Eukleidas’ men with missiles, the more heavily
armed soldiers began hacking their way into the foe, desperate to gain a
foothold on the hill’s summit.

At the foot of Olympos, meanwhile, Antigonos easily steered
his great double-depth phalanx up the gentle slope toward Kleomenes’ position
at the fortified summit. With much less vegetation and far smoother terrain,
Olympos offered the king a far easier ascent than that which Euas provided. Up
ahead, however, Antigonos could see large groups of light-armed soldiers moving
out from behind the Spartan fieldworks, intent on hindering his progress. As
his forces were now close enough to threaten Kleomenes with a sudden attack if
he attempted to move units to support Eukleidas, Antigonos ordered his troops
to halt a scant hundred yards from the enemy defences. In the valley below, his
centre also halted, having been instructed to wait for Antigonos’ signal to
close with the Spartan centre. Now, as Antigonos ordered forward his
skirmishers to meet the enemy light-armed some distance up Olympos, only his
right wing continued the advance, pressing ever onward toward the summit of
Euas.

As the Macedonian and Illyrian phalanx marched on toward the
sound of battle, intermittent showers of javelins, stones and arrows began to
fall on their formation. Eukleidas, for his part, was not taking the Antigonid
assault lying down, as once the enemy were seen moving up the hillside, the
general immediately dispatched part of his light infantry to try to break up
their surprisingly resilient formation. Discredited by many historians and
tacticians for not launching a wild downhill assault at the oncoming foe, it
should be remembered that Eukleidas had been ordered by Kleomenes to entrench
and fortify Euas, with the obvious intention of holding the palisade at the
hill’s summit. The king probably intended to use Euas as a pivot and anchor on
which his stronger right wing could safely turn. He seems not to have imagined
that the smaller, steeper prominence could be attacked in flank and in force by
the whole of Antigonos’ right wing. For these reasons, and likely due in some
measure to simple hesitation and uncertainty (not to mention the dangerous
flank attack), Eukleidas failed to give the order, as his brother later would
on Olympos, to tear down the palisades and hurl the full weight of his men upon
the enemy below. Even had he done this, against Antigonos’ Bronze Shields
Eukleidas’ light infantry and equally poorly-armed mercenaries would have
likely had little effect.

Despite this imagined failing, Eukleidas was an astute
enough commander to recognize another opportunity to damage his opponents. When
Antigonos’ centre halted to await the king’s signal to attack and his left
continued on, a gap opened between the Illyrian unit on the left flank of the
phalanx and the mixed cavalry making up the centre’s right flank. Undaunted by
their lack of protection, the men of the phalanx pressed on, but as they drew
near to the enemy fortifications, a large force of light infantry suddenly
appeared off their left flank. These troops, drawn from the Spartan centre and
left, had been ordered by Eukleidas to attack the exposed phalanx. They obeyed
with terrifying speed, flinging themselves onto the panicked Illyrians, who
could only weakly fend off their unexpected onslaught. Unable to change face to
deal with this threat, the advance of the left flank of the phalanx quickly
ground to a halt as chaotic fighting threatened to overwhelm the endangered
units. This surprise attack placed not only the Illyrians in jeopardy, but also
the rest of the phalanx, which had become precariously disordered as units on
the far right continued their advance and others nearer the actions slowed and
sought to help their comrades. While the Illyrians fought and died trying to
fend off their tenacious assailants, other enemy units were working their way
behind them in an effort to attack the rear of the Illyrian formation and bring
about the disintegration of Antigonos’ entire right wing. Just as these units
closed in for the kill on the wavering Illyrians, however, a rising commotion to
their rear caused some to turn and look.

Barrelling toward them was a portion of Antigonos’ cavalry
from his withheld centre, led by the impetuously brave Philopoimen. Having
earlier spotted the approach of Eukleidas’ counterattacking light infantry, the
young Achaian officer dashed to inform his commander, a general by the name of
Alexander, who nevertheless refused to order an attack, insisting that
Antigonos would signal when the time was right. Frustrated by this cowardly
reluctance, a distraught Philopoimen watched as the enemy light infantry
ploughed into the struggling phalanx and began to roll up the Antigonid force.
Finally, unable to control himself any longer, the headstrong leader called
upon the men of his city to follow him as he set spurs to his mount and
careened forward. Many other cavalrymen, similarly distressed at the failure to
engage, also bolted ahead and soon hundreds of horsemen were charging toward
the backs of their foe who, preoccupied in mauling the Illyrians, were
oblivious to the danger thundering up to meet them.

At the opposite end of the field, the battle had begun in
earnest on Olympos as well. There, while his mercenaries and light-armed troops
sparred in increasing intensity with the enemy light troops, Antigonos watched the
situation developing in the valley below with concern. Slamming into the backs
of the preoccupied Spartan light troops, Philopoimen’s cavalry instantly broke
the enemy’s heretofore victorious ranks and sent them running for their lives.
At this point the rest of Antigonos’ centre pressed ahead in a full out attack
on Kleomenes’ centre while the Macedonian and Illyrian phalanx resumed its
assault on the heights of Euas. Screened by a force of light infantry, who
flung missiles at the defenders and sought to tear down their palisades, the
articulated phalanx of Antigonos’ right wing reached the summit and began the
bloody work of storming through the defensive ditch and over the makeshift wall
Eukleidas’ men had erected. The Illyrian and Akarnanian flankers, meanwhile,
had forced back the improvised Spartan flank guard and broken into the rear of
the defender’s position, plunging the Spartan force into chaos. By the time the
full weight of the Bronze Shields was brought to bear against Eukleidas’ men on
Euas, the battle was virtually over. The survivors of the struggle fled in
terror down the reverse side of the hill in a desperate attempt to reach the
walls of Sellasia.

Meanwhile, Kleomenes’ centre had advanced in response to the
thrust by Philopoimen and now a cavalry battle was raging in the valley between
the two hills. Splashing back and forth through the shallow Oinous River,
squadrons of Spartan and Antigonid cavalry clashed amidst swarms of light-armed
infantry and mercenaries. At one point the fighting in this brutal encounter
grew so fierce that Philopoimen’s horse was killed under him and, as he
continued the fight on foot, the intrepid Achaian was seriously wounded by a
javelin. Tearing the projectile from his leg, the young soldier amazingly continued
to fight, shouting encouragement to his men and directing others toward the
critical points of the struggle. As Antigonos’ right wing swept the remaining
Spartan troops from Euas and his cavalry began to drive back the outnumbered
Spartan horsemen, the king confidently estimated that the engagement would soon
be over.

Kleomenes, who had watched in despair the loss of Euas and
the brutal battering his centre was taking, now saw the total collapse of his
army looming before his eyes. Already Antigonos’ right-wing units were
advancing toward the foot of Olympos to take his phalanx in flank just as had
been done to his brother. In his desperation to avert a complete defeat, the
king ordered a bold, some say foolhardy, manoeuvre. Directing his light
infantry and mercenaries to redouble their efforts and drive off Antigonos’
screening force, Kleomenes instructed his phalangites to tear down their
fortifications in preparation for an advance. Cheering at the chance to finally
strike a blow against the hated Macedonians, the Spartan troops demolished
their palisades and made ready to charge into the melee below. With Antigonos’
troops moving up the flank of Olympos, intent on surrounding the Spartan
phalanx, Kleomenes saw no other option but to charge.

Rolling down the hillside like an unstoppable tidal wave,
Kleomenes’ men collided with Antigonos’ thirty-two-rank-deep Macedonian phalanx
with stunning force. Parting before them, the light infantry scattered to the
flanks where they resumed their deadly work, leaving only bodies strewn across
the field that now belonged to the battling phalanxes. Though his men braced
for the collision, Antigonos’ formation buckled as his soldiers were forced
back by the sheer stunning weight of the impact. As sarissa plunged past
sarissa and the two great hedgehogs locked together in a desperate struggle,
the ground over which they trod quickly became littered with the bodies of
hundreds of Spartan and Macedonian phalangites. Tripping on corpses and
struggling to stay in formation, the battle grew even more intense as the men
of Antigonos’ phalanx managed to force back their attackers, driving them back
up the hillside. For some time a bloody cycle developed whereby the fluctuating
momentum and weight of the attack shifted from one side to the other
accompanied with a subsequent gain or loss of ground.

Driving his phalanx mercilessly into Antigonos’ men again
and again, Kleomenes exhorted his troops to do their utmost and leave no energy
unspent in their efforts to crush the foe. Not only their lives, but their very
way of life depended on it, and therefore they could not fail. After a
particularly savage reverse in which his men were pushed far down the hill,
however, Antigonos realized that the strain his opponent’s fanatical attacks
were placing on his men would soon become intolerable. Shouting orders to his
officers, the Macedonian king watched his soldiers instantly shift positions as
his command flew throughout the phalanx. Compressing the distance between their
files to the ‘close order’ formation, each soldier drew himself up literally
shoulder to shoulder with his neighbour. Roaring their battle cry, the Macedonians
launched a ferocious counterattack, charging into the Spartans with all the
strength left in them.

Confronted with a reinvigorated phalanx and a virtually
invulnerable wall of spear points, Kleomenes’ men, alarmed and exhausted, were
overwhelmed. Forced back up the hillside in increasing disorder, the end came
for the Spartans as thousands of screaming Illyrians and light infantry from
Antigonos’ right wing charged up the last few yards of sloping ground, crashing
into the back-pedalling phalanx on its exposed flank. At this point, with his
army collapsing around him, Kleomenes knew he could do no more. As their lines
broke and his men panicked and ran in terror, the battle became a massacre,
which the Spartan king fled as his men fell by the thousands. The power of
Sparta was forever broken; Antigonos had triumphed.

The Aftermath

For Kleomenes, Sellasia was a battle that probably could not
have been won.140 Outnumbered and outclassed by the army of Antigonos, the
Spartan king could do little more than shelter in his ingeniously chosen
location. A strong defensive position alone cannot secure victory, however, and
given enough time, even a poor general will discover the flaws of any given
defensive posture. As has been seen, Antigonos was no novice on the battlefield.

The Spartan army which Kleomenes had spent years shaping and
training was virtually annihilated at Sellasia. When Euas fell many of the
defenders fell there as well, though some were known to have escaped by fleeing
down the reverse slope. The cavalry and other troops in the centre may have
fared better than most, with their easy access to the valley and the road to
safety and while great numbers of mercenaries were killed on all fronts of the
battle, by far the heaviest losses of the conflict were suffered by Kleomenes’
own soldiers. Of the 6,000 Spartans in the phalanx on Olympos, only 200
survived the slaughter. Antigonos’ men also suffered heavily, especially during
the assaults on Euas and Olympos, but their losses were nowhere near as severe
as their opponent’s.

Having placed his faith in the security of his hilltop flank
on Euas, Kleomenes spent the rest of the battle attempting to bring events back
under his control after its unexpected fall. Sadly, his last-ditch attempt to
crush the Macedonian phalanx on Olympos, though heroic, could not have
succeeded, as Antigonos’ right wing units would have rapidly surrounded his men
regardless of any local success he might have achieved. Though the hammering
encounter on the slopes of Olympos underscores yet again the lethal brutality
of the Macedonia phalanx, Kleomenes’ defeat was accompanied by an even more
stinging lash of irony. Entering Sparta in triumph a few days after the battle,
Antigonos became the first foreign commander ever to capture the city. Soon
thereafter news reached the king of an Illyrian invasion of Macedonia, which
caused him to march immediately to the relief of his kingdom, leaving the
Peloponnese entirely. Had Kleomenes been able to delay Antigonos for but a
handful of days longer, the Macedonian would have been forced to withdraw and
history may have played out very differently.