Military Reforms of Alexander the Great

It is 336 BC and Philip II of Macedon is dead. In his lifetime, he had completely overhauled the Macedonian army, transforming it into the greatest force the Hellenic world had yet seen. In this episode, we shall cover the evolution and reorganization of the Macedonian army during the reign and conquest of Philip's son, Alexander the Great. Arguably, the element of Macedonian army that evolved the most during Alexander's conquests was his siege machinery. Just as his father had before him, Alexander quickly embraced the great potential of siege warfare for his campaign. Ladders remained the most cost-effective way to capture a settlement and we know Alexander took many smaller towns using them. Yet, to conquer the more formidable defences of the larger Achaemenid fortresses, Alexander required more complex, awe-inspiring engines. Just as Polyidus was for Philip, one engineer was crucial to the evolution of siege machinery during Alexander's infamous campaign. His name was Diodes. A resident of Pella, Diodes had been a student of Polyidus and succeeded him as chief engineer at the time of Alexander's secession. Diodes would create several new siege engines during Alexander's reign. Arguably, one of the greatest was the troponon, the borer. Designed to ram down a settlement's walls, simple borers had been in existence before Diodes. Yet, it was he who radically improved its design. Like the ram, Diodes' borer consisted of a wooden beam with a metal head. It would be attached with ropes that were connected to pulleys and winches, so when the mechanics pulled the ropes, it would exert a powerful force on the ram and cause a large breach in the wall. Diodes not only increased the borer's power, but also its protection. The beam was placed inside a mobile wooden shield called a chelone, or tortoise. Alongside the borer, Diodes invented many other formidable siege engines. This included a grappling machine designed for pulling down defences and a much-improved drawbridge called an epibathra. This drawbridge acted as a gangway, which soldiers could use to cross over from either a siege tower or ship. Although the drawbridge had been in use before Alexander's time, it was Diodes who dramatically increased its effectiveness. Diodes would also make modifications to many existing siege engines, such as the ram, protected with a tortoise, and the siege tower, increased mobility and better drawbridge. Many of these engines would be used during Alexander's successful siege of Tyre, arguably Alexander's greatest military feat. Consequently, Diodes became known as the man who took Tyre. There were other engineers that accompanied Alexander. The talented engineer Carius was essential in the creation of various siege machines designed to counter specific defences. At Halicarnassus, for example, we hear the Macedonians employed ditch-filling tortoises to aid an assault on the city. Another prominent engineer, Poseidonius, would design a modified siege tower for Alexander. Its wheels were mounted on a sturdy timber chassis, which provided a strong base for the tower. Inside the chassis, 150 men would man the contraption that would push the engine's wheels towards the enemy wall. As well as containing other levels for stone-throwing torsion catapults or lithoboloi, the tower had two main floors. One floor was placed at a level that would be the same height as the opposing battlements. The other level was placed higher up, level with the top of a defending tower. A drawbridge would be lowered when the tower reached the wall, through which the attackers would cross over onto the defences. Facing such a complex and deadly mobile machine must have been terrifying for any defending force. Significant developments would also be made to Alexander's artillery throughout his campaign. Poleidas' creation of the torsion catapult under Philip was revolutionary for siege warfare, and Diodes and his fellow engineers continued to improve upon his initial design. By the start of Alexander's Persian conquest, no longer were these torsion catapults used to primarily fire arrows at the defenders themselves. Thanks to further advancements, they were now able to also fire stones with enough power to smash down enemy walls. They were called lithoboloi or stone throwers. Very quickly, Diodes, Carias and the rest of the Macedonian engineers made further improvements to these lithoboloi. At the sieges of Halicarnassus and Tyre, for example, we hear of highly destructive torsion stone throwers called petroboloi being used in Alexander's army. These devastating machines could either be wheeled or wheelless and could be placed on land, on siege towers and on ships. Alexander continued to use other types of artillery, such as the arrow-firing torsion catapult, the successor to the non-torsion oxybelis used by his father. Each of these machines provided covering fire for his troops and were manned teams of specialized artillerymen. What made these great engines even more fascinating was their portability. It was Alexander who truly embraced the concept of designing siege equipment that could be dismantled and reused elsewhere. Throughout his campaign, both by sea and land, his army's great siege engines were dismantled, transported and then reconstructed at various locations. During the siege of Gaza, for example, Alexander ordered Diades' siege engines used at Tyre to be dismantled and transported by sea to be quickly reconstructed. The Macedonian infantry and cavalry would also evolve during Alexander's reign. Upon his accession, Alexander inherited the most revered infantry force of the time. Yet, he would quickly instigate changes to it. Perhaps to ensure their loyalty, Alexander quickly extended the name peshetairoi, or foot-companions, to include the entirety of his phalanx, while the elite infantry of Philip II became known as the hypaspists. Whether the peshetairoi of Philip were the same soldiers who formed the hypaspists of Alexander is unknown. The peshetairoi of Alexander's army experienced no significant changes for much of Alexander's conquest. Its soldiers remained in basic units of 16 men, called a dekas, which could be combined to form a lokos of 128 men. Twelve of these lokoi combined formed a battalion of 1,536 men. Small changes in structure, however, do appear to have occurred for the hypaspists. New sub-commanders appointed by merit were introduced into the elite unit. Companies of 500 men were commanded by a pentakosiak, while units of 1,000 were commanded by a kiliak. The hypaspists consisted of 3,000 men in total, so the unit had 6 pentakosiaks and 3 kiliaks altogether. Later, following Alexander's death, his hypaspists would receive a new name to reflect their high quality – the agaraspedes, or silver shields, used most notably by Eumenes during his great campaign against Antigonus. From the Granicus in 334 BC to the Hydaspes in 326 BC, the Macedonian phalanx was the nucleus of Alexander's army. Yet, as Alexander's campaign went on, reinforcements from Macedon ended, and the number of his foot-companions slowly dwindled. Alexander lost many of his Macedonians due to death, injury, old age, or being settled somewhere in his empire, and by 324 BC, less than 10,000 remained. Alexander had no option but to radically reorganize his Macedonian phalanx, incorporating Iranian infantry into the battalions. In each decus, only four of the 16 men remained Macedonians, stationed at the front and rear in the formation. The rest were Persian levies, not trained with the sarissa, and instead using their native armaments, the bow and javelins. This mixed phalanx lacked the cutting edge and flexibility of the original, and thus did not stand the test of time following the death of Alexander. Alexander had seen this as a temporary measure, yet he still needed to bridge the divide between the conquered and the conquerors in his army if he were to be a legitimate king of Asia. One way he realized he could do this was by removing his reliance on his Macedonian infantry and improving the quality of his Asian footmen. In 327 BC, Alexander ordered 30,000 Asians to be recruited and trained in the Macedonian manner. Trained by Macedonian veterans, these oriental youth would undergo constant practice in the use of Macedonian arms and discipline for the next two years, separate from their Macedonian counterparts. At the beginning of 324 BC, they were presented to Alexander at Susa, dressed in Macedonian attire, well-trained in the sarissa phalanx and a rival to the Macedonians themselves, so much so that Alexander labelled them as his epigoni, or successors. By the end of 324 BC, Alexander's powerful Macedonian sarissa phalanx was no longer the undisputed key infantry force in his army. Now there was a rival, equally prestigious formation in Alexander's force. The Macedonian cavalry too evolved during Alexander's reign, most notably with the companions. Philip had arranged his companions into ile squadrons, based on the regions where they owned their land. Each squadron, 200 men strong, was commanded by a squadron leader called an iliarch, who wielded great power in the field. Alexander altered this. In 331 BC, perhaps to curb each squadron commander's power, Alexander began to reform the command structure. He divided each ile into two smaller units called lokoi. In charge of each of these, he appointed new sub-commanders called lokogoi. These appointments were based on merit, and not the region associated with each squadron. These lokogoi owed their newfound power to Alexander, and their loyalty became unquestionable. The power of the original iliarch was curbed significantly, as was the regional affiliation of each of the squadrons. In 330 BC, Alexander made a crucial decision that would forever change the organization of his companions. Philotas, the son of Alexander's second-in-command, Parmenion, and the overall commander of the entire companion cavalry body, was accused of being involved in a conspiracy against the king, and duly executed along with his father. Alexander then divided the command over his companions between two of his closest friends, Cleitus the Black and Hephaestion. Never again would he allow one man total control of his elite cavalry unit. Furthermore, Alexander changed the name for the basic unit of the cavalry. From 330 BC onwards, he no longer labelled his companion regiments as ile squadrons, but hipparches. The term ile continued to be used as a subdivision of each hipparche, with two ile squadrons together forming one hipparche. As for the royal squadron or basilica ile, this too appears to have had its name changed at this time to the agema. Consequently, Cleitus and Hephaestion also received a new title, and were called hipparches. By 327 BC, Alexander increased the number of hipparches commanding the companions to eight, including men such as Perdiccas and Craterus, who would later become the Diadochi. Alexander would also introduce oriental horsemen into his companion cavalry. By 324 BC, four hipparches of the companions consisted solely of picked Iranian cavalrymen, and a fifth contained a mixture of oriental and Macedonian horsemen. We also know that certain Asian nobles were incorporated into the royal agema. Consequently, the companions were no longer a select Macedonian unit from the region's nobility. With the creation of the foreign hipparches of the companions and the epigone, certain oriental units had become just as prestigious as his Macedonians by the end of Alexander's reign. It was not just the companions that Alexander greatly reorganized, however. Great change also appears probable to the Macedonian light cavalry, the prodromoi. Following 329 BC, any reference to the Macedonian light cavalry disappears completely from our sources. What happened to the prodromoi is unknown, although many now suspect Alexander merged them with his reorganized companions and placed them within the new-look hipparches. From then on, Alexander's light cavalry came mostly from his Asian units, such as his horse archers from Dahe. By the end of Alexander's reign, the Macedonian army had significantly evolved from that of his father Philip. We will cover other critical parts of his army in the next episodes, so make sure that you are subscribed to our channel and have pressed the bell icon to be notified of our videos. We would like to express our gratitude to our Patreon supporters and YouTube sponsors, who make the creation of our videos possible. This is the Kings and Generals channel, and we will catch you on the next one.