"All warfare is based on deception" – Sun Tzu

My lord, let us now consider the proper use of the phalanx, and study how Pyrrhos employed it in the hills of Thessalia. Stout phalangites have always been at the heart of any army of the Epeirote homelands, and they form the perfect anvil on which to use the hammer of your cavalry. Of course, the enemy knows this too, and thus we must sometimes use deception to tempt them into spearing themselves on our sarissas.

Pyrrhos well understood the power of the phalanx, and while he busied himself with pacifying the city of Pella he also sent word west, ordering the levy of an additional 4,800 phalangites from Ambrakia. These troops marched across the mountains through the winter snows, and with their arrival Pyrrhos moved his army into the field once more. The Antigonids were still fighting ceaselessly in the south against the city-states of Athenai and Sparte, but they had significantly increased the garrison of Demetrias in the province of Thessalia. It was this garrison that Pyrrhos now faced, and here we come to an important lesson: the proper choice of both battle and battleground.

The phalanx is at its heart a defensive formation, and does best when the enemy is forced to attack. For then our troops can merely stand their ground, while our foes must wear themselves out trying to break through a solid wall of spearpoints. We must therefore always strive to tempt the enemy into attacking us, rather than vice versa. A wise general will also fight the battle on ground of his own choosing, and here Pyrrhos chose perfectly, stationing his army in a high pass on the coastal road between Pella and Demetrias.


Pyrrhos chooses his battleground on the coastal road

Demetrias was governed at this time by Kalos Argeades, a rather dull and disloyal member of the Antigonid family. He wanted the glory of defeating Pyrrhos but none of the personal risk, and thus in the spring of the second year of the 127th Olympiad (271 BC) he sent the bulk of his garrison out to battle under the command of a simple captain, while he himself waited in Demetrias. A more prudent general might have waited for Pyrrhos to besiege Demetrias, and a more loyal one might have commanded the army himself. From Kalos's personal papers we learn that while Makedonian spies had reported the elephantes leaving for Ptolemaic lands, they had not seen the other changes to Pyrrhos's army. For in addition to doubling the number of phalangites in his army, Pyrrhos had also added a strong force of 2,000 cavalry from Illyria (Illyrioi Hippeis). These horsemen are lightly armored and somewhat unruly, but they ride very hardy horses from the mountains of Illyria. They are well suited for repeated charges into the rear of an enemy pinned on our phalanx, and are able through their ceaseless activity to wear out any who choose to pursue them. A light hammer, but one that you can use throughout the battle!


Forces present at the battle of Thessalia, 271 BC

Consider now the forces available to both commanders, and then think on the odds if Pyrrhos had not added the Ambrakian phalangites and Illyrian cavalry. Might not the outcome have been different? The force sent from Demetrias included elite heavy cavalry with sturdy horses from the surrounding Thessalian plains (Hippeis Thessalikoi), professional hoplites from the polis of Demetrias who could withstand a frontal attack by Pyrrhos's Galatian mercenaries, and a band of Agrianian assault infantry able to make short work of any phalanx that they could flank (Agrianikoi Pelekuphoroi). The Makedonians thus brought a force of over 11,000 infantry and 1,000 heavy cavalry to the battle, facing an enemy they thought numbered 13,000 infantry and Pyrrhos's own bodyguard cavalry. In fact Pyrrhos had almost 18,000 infantry, supported by 2,000 light cavalry.

We can thus imagine that the Makedonian captain had a false expectation of success, or at least of an honorable draw, as he marched his forces down the mountain road to meet Pyrrhos. However, when he first saw the long rows of Epeirote sarissas waiting for him, a quick count should have told him that Kalos's spies had not done their work properly.


The Epeirote phalanx waits on perfect ground for the enemy to attack

And at this point, my lord, the Makedonian captain should also have considered what else had not been seen by the spies. For Pyrrhos had ordered his cavalry to position themselves far in advance of his other forces, in the trees along both the sides of the roads, and there they stayed hidden throughout the early stages of the battle. Unaware of this danger, the Makedonian captain marched his forces up in good order, positioning his hoplites and phalangites to meet the long Epeirote line arrayed across the road, and engaging in an initial skirmisher battle, as is the custom in Hellenic armies.


The Makedonian line approaches in good order

The Makedonian captain knew that to break a phalanx you must flank it, and as his troops advanced to contact he tried exactly this, sending half of his professional hoplites to Pyrrhos's left, and the Thessalian cavalry to Pyrrhos's right. Now we see the perfection of Pyrrhos's choice of battleground, for while his phalanx blocked the open ground, he had hidden his other infantry further back in the woods on both flanks. Thus the hoplites suddenly heard the fearsome war-cries of Galatian mercenaries charging out of the woods behind them, while the horsemen of Thessalia blundered directly into Illyrian spearmen, eager for more glory after their deeds at Pella. Hoplites find it more difficult to maintain a solid line in woodland, and cavalrymen are particularly vulnerable amongst the trees, which is why such lowly spearmen were able to take on the elite of Thessalia.


Galatian mercenaries and Epeirote phalangites chase routing Makedonian hoplites into the trees

A brief charge from Pyrrhos helped break the will of the Thessalians, and they fled the field, pursued by the spearmen. The Galatians were similarly pursuing fleeing hoplites. This left the two main battle lines engaged, and a unit of Epeirote phalangites even advanced beyond the line to engage the Agrianians, who had been kept in reserve by the Makedonian captain. In any other situation this use of an isolated phalanx would be foolhardy, for the Agrianians could gradually thin their lines and wrap around the phalanx, chopping at its vulnerable sides and rear with their fearsome axes.


The line is fully engaged – note the isolated Epeirote phalanx in the upper right, facing Agrianian infantry

However, this was also the moment when Pyrrhos's horn called the Illyrian cavalry into action, charging down the hill from their hiding places. Quickly routing the Agrianians, they then turned their attention to the Makedonian captain's unit, and when their second charge killed him this was the true end of the battle. Kill the head of an army and the rest of it will surely crumble, and this was the fate of the Makedonian forces that day.


The first Illyrian cavalry charge of the battle, which broke the Agrianian reserves

As a last lesson, my lord, even the positions of the dead can tell the story of a battle to an eye trained in war. Here the bulk of the enemy lay in a single line across the road, marking where they had fallen to a sarissa in the chest or a lance in the back. Leading back from this were thin lines of sad corpses, almost all with wounds in the back, marking the demise of men cut down as they routed. Few made it back to Demetrias to tell Kalos of the crushing defeat.


Makedonian dead lie strewn across the field

A well-led army based on a strong phalanx will generally suffer few casualties compared to those of the enemy, and such was the case in Thessalia this day. Pyrrhos's skirmishers suffered most, and even the Illyrian spearmen gave a good account of themselves fighting elite cavalry, covering themselves in further hard-won glory.


Casualties of the Battle of Thessalia, 271 BC

Wasting no time, Pyrrhos pursued the Makedonian survivors to the gates of Demetrias, and there invested the town in a siege. In my next missive I shall discuss the true reasons behind Pyrrhos's remarkable decision to then split his forces, and the lessons to be drawn from the resulting battles.

I was pleased to hear of your first victory against a rebel band. From such skirmishes are great generals made! I would urge you, however, to pay heed to the counsel of your veteran captains. They are still more experienced in the ways of war than your esteemed self, and their advice could help reduce casualties in future battles.