Alexander – even today, 23 centuries after his death, his name still has the power to inspire. His achievements have stood the test of time and remain amongst the most remarkable in the whole annals of military history. With an army of typically only around 40,000 men, he conquered the largest, richest and most powerful empire the world had ever seen; and all of this in less than a decade.
When Alexander became king, his military career began when he launched a campaign against Macedonia’s northern neighbours. This is a campaign that we know little about, but we can assume that it was remarkably successful given that Antipater, his regent, never had any difficulty from that region. From there, Alexander marched in central Greece, and sent a terrible message with the destruction of the ancient city of Thebes.
In 334, Alexander crossed the Hellespont and invaded Asia. He soundly defeated the Persians in large set-piece battles at the Granicus River, Issus and finally Gaugamela in 331. During this period he also captured the great fortresses of Halicarnassus, Tyre and Gaza. After the death of Darius, Alexander spent several years campaigning in Afghanistan and India; a brutal period culminating in the defeat of the Indian king Porus at the battle of the Hydaspes.
In India, the army had finally had enough and refused to march further into the unknown. They turned back and made a disastrous march through the Gedrosian Desert. After a final siege during which Alexander was struck by an arrow that punctured his lung, he returned to Babylon where he died in 323.
Alexander’s incredible string of successes was not accidental; listed here are the 10 main reasons for them (in no particular order). You can find out more about Alexander as a military commander in my books, The Army of Alexander The Great and The Sieges of Alexander The Great, both published by Pen & Sword.
1. Philip of Macedon
Philip, Alexander’s father, was one of the finest military minds of the ancient world; but he is completely overshadowed by his son. Philip took a broken kingdom that was about to be overrun by foreign enemies, and turned it into the most powerful state in Greece. Shortly before his death he sent an expeditionary force to Asia Minor to conduct an initial campaign against the Persians whilst he prepared for a larger invasion.
Had Philip lived – he is believed to have been buried at Aigai – he clearly would have expanded upon this expeditionary campaign with a full scale invasion. It is always interesting (but ultimately fruitless) to speculate how Philip would have fared compared to Alexander.
Alexander had a first rate military education watching the successes of his father, and evidently was worried that there would be nothing left for him to conquer if his father continued too long; the assassin’s blade ensured that this would not be the case.
Could Alexander have achieved what he did without his father’s foundation? This is a difficult question to answer, but I would suggest that Alexander had the ability, but his character would likely have let him down. Alexander clearly had the ability to reorganise the army and to develop innovative strategies and tactics as required, as well as his natural military genius. We must recognise, however, that it would certainly have taken rather longer because the army would have needed to be trained and turned into the machine that Philip had already created, and the question also remains as to whether Alexander would have had the patience to delay his ambition; patience is not a trait that Alexander ever demonstrated to any great degree.
2. The Army
Alexander’s greatest inheritance was the Macedonian army. At the time of the invasion of Asia Minor, the historian Diodorus tells us that it consisted of 5,100 cavalry and 32,000 infantry. This was a respectable size by Greek standards, but tiny in comparison with the number of troops Darius could put in the field. Of the 37,100 troops, the Macedonian contingent was relatively small: 1,800 Companion Cavalry and 12,000 infantry. These were by far the most important troops Alexander commanded, and the main weapon with which he gained an empire.
This army was a very complex organisation of interlocking and mutually supportive parts. Alexander created what was probably the first combined arms force in world history: he developed a series of units that excelled at specific tasks, but retained tremendous operational flexibility. Individual units were highly trained and some were highly specialised: the hypaspists, for example, were employed to maintain a cohesive link with the Companion Cavalry during the set-piece battles; if they failed then a gap would have opened in Alexander’s line that the Persians could have exploited.
Light infantry, specifically the Agrianians, were assigned specialised tasks, and even fought alongside the cavalry units at Gaugamela. Later the Dahae horse archers were deployed with devastating effect against the Indians at the Hydaspes. The heavy infantry could operate together, or as individual taxis (battalions). Each of the individual units of Alexander’s army were dangerous if engaged independently, but when combined formed an army that was one of the finest the world had yet seen; when this was coupled with the tactical genius of an Alexander, the results are there to see. Each element of the army was highly trained and supported every other element. This was a true combined arms force as described The Army of Alexander The Great.
Another, perhaps more accurate word, would be stubbornness. Alexander was remarkably stubborn and never let any obstacle, be it natural or manmade, stand in his way. When faced with the city of Tyre, he refused to allow it to remain a “free city” offering safe harbour to both Greek and Persian fleets. He did not possess any significant navy at the time so he set about constructing a mole to join the island fortress to the land. Later in his career, we see a string of similar sieges on the north-east frontier and in India where he had to build a series of wooden bridges over deep ravines. He repeatedly captured seemingly impregnable fortresses, like Aornus, and never accepted any obstacle as being insurmountable.
This is a much over-used word in today’s society, but by whatever measure we employ, Alexander was without question a military genius, perhaps the greatest the world has ever seen. Alexander was the finest strategist and tactician the ancient world had yet seen. He repeatedly demonstrated an ability to successfully fight campaigns in every theatre of war the ancient world had to offer (although his naval experience was limited to the later stages of the siege of Tyre), and to continuously adapt his strategies and tactics to every emerging circumstance.
Alexander also demonstrated an ability to analyse the evolving circumstances that the Afghanistan region presented, and changed the organisation of the army to deal with the new threat of guerrilla warfare. Alexander’s sense of timing during his set-piece battles was also remarkable. The timing of his decisive cavalry charge was always immaculate, and the result devastating. He had a genius for analysing a situation and instantly making a judgement of what was needed. His set-piece battles are analysed in my forthcoming book The Field Campaigns of Alexander the Great.
I touched on this in an earlier point, but Alexander showed throughout his career an amazing ability to adapt to changing situations and circumstances. He essentially used a relatively small number of successful tactics and tactical ideas, but these were constantly being adapted and modified as circumstances changes.
Alexander’s fundamental tactic was to attack in more than one direction simultaneously. We see this in his set-piece battles where he times his attacks so that the Companion Cavalry strike the flank of the enemy infantry at the same time the heavy infantry attack from the front. The battle of Issus – depicted on the Alexander sarcophagus – is a perfect example of this; this battle is a series of brilliantly executed flanking manoeuvres.
We also see this during his many siege operations. At Tyre, Alexander attacks from the mole, but also had artillery, siege towers and scaling ladders mounted on ships so the fortress can be attacked from multiple directions. This happens at Gaza too, where the city is attacked from all directions to distract from the main thrust of the assault.
Alexander’s sub-commanders are a remarkable array of talented individuals, many of whom became kings in their own right after Alexander died and his empire was broken up. These successors, the so called diodochi, included men like Antipater, Ptolemy, Seleucus, Antigonas, Perdiccas and Lysimachus and Cassander. Any successful general required his subordinates to have some measure of ability. He needed his orders to be conveyed to the rank and file, and he needed them to be carried out. This would not have happed with a rather less talented bunch. There is no question it helped Alexander to have commanded such a talented group of individuals, but the question for another day must be: would these men have been kings and statesmen without Alexander? We will never know, but their careers were certainly helped by the Great Macedonian.
We hear very little about the Macedonian logistics system in the sources, but we know that it was very good because we also hear of very few instances where it failed and the army struggled. The baggage train, which the Macedonian army could not have done without, was kept to a minimum size during Alexander’s early career, following reforms by Philip. This enabled the army to move rapidly and strike without warning. It also meant that the army could move quickly from region to region without exhausting the resources of any area.
The main example of the failure is the march through the Gedrosian desert. Many died of thirst or hunger during the march. The army and the logistics system were simply not prepared for this environment. This is an example of Alexander’s stubbornness getting the better of him. Apart from the (usually) excellent supply of food and water, we hear almost no examples of a lack of horses, weapons or armour. The only possible hint of difficulties is in India when the army rebelled against the prospect of further conquest.
This is a concept that we usually associate with the German army of World War II, and the changes that Heinz Guderian introduced. In the most basic of terms it revolved around rapidity of movement and the concentration of force. Alexander was its first exponent in history. The Macedonian army under Alexander was capable of remarkable feats in terms of their rate of march. They frequently exceeded 30km per day, and could keep this up for several days allowing them to arrive at a battlefield long before they were expected, and before the enemy was prepared. When news reached Alexander that Thebes had rebelled, he was in the Balkan region, having recently captured Pellium. He marched 390 km in 13 days to arrive at the walls of Thebes before they had properly prepared their defences. This is a remarkable rate of march, but when we consider the mountainous terrain of the Greek mainland, it is even more amazing. During the brief siege, the troops showed no signs of fatigue, either.
9. Motivational Leadership
Alexander had remarkable personal charisma; he had an almost superhuman ability to inspire his men to ever greater pinnacles of achievement. He led an army from the Balkans to the heart of India before they showed any major signs of discontent. When they left Macedonia in 334, many did not return home, and those that did had been away for 10 years or more.
Alexander’s ability to inspire his men is one of his most admirable qualities. He did this in a number of ways; certainly he made speeches before battles, all ancient commanders did, but more than this he made a point of leading from the front. He never expected his men to undertake any dangers that he was not prepared for himself. He was the first over the wall at the siege of the city of the Mallians, for example. He also made a point of trying to remember the names and achievements of some of his rank and file, and to comment to them whenever he had the opportunity. This is a tradition that was carried on during the Roman period and became the hallmark of a good general.
Anyone who is successful in any field needs luck, and Alexander was no exception. He is certainly lucky to have survived as long as he did; he was wounded by almost every weapon of war available to the ancient world, and came so very close to being decapitated at the battle of the Granicus in 334. He is also lucky he had Philip for a father, and that he inherited the finest war machine the world had yet seen. Xenophon’s march to Cunaxa had demonstrated that the Greeks were capable of defeating the Persians, if only someone could unite (or conquer) the Greeks long enough to do it. Philip looked like he could have been that man, but in the end Alexander was the one to finally bring down the Persian Empire. Alexander’s career represents a remarkable nexus of events rare in history. He was exactly the right man in the right place at the right time, and he grasped his opportunity for immortality.