Alexander the Great’s invasion of the Persian Empire of Darius III presents an excellent example of the persisting strategy of aiming at occupation of the enemy’s territory. Alexander’s political
objectives were too ambitious to attain even by the very extensive and destructive raids his huge army could have carried out in Persian territory.
With as many as 35,000 and perhaps nearly 50,000 infantry and cavalry, Alexander had a larger army than the Persians forces in Anatolia and a formidable weapon system essentially unknown to the enemy in his Companion heavy cavalry. Although the Persian army had a strong force of hired Greek hoplites, it recognised Alexander’s preponderance in infantry. In the absence of the King, this provoked a debate among the Persian generals as to whether their strategy should embrace combat against Alexander’s men or whether they should direct their efforts toward defeating his army by destroying its logistic base.
The leader of the Greek infantry advised the council of generals and governors “not to risk a conflict with the Macedonians, since they were far superior to themselves in infantry, and
Alexander was there in person; whereas Darius was not with them. He advised them to advance and destroy the fodder, by trampling it under their horses’ hoofs, to burn the crops in the country, and not even to spare the very cities. ‘For then Alexander,’ said he, ‘will not be able to stay in the land from lack of provisions.’” Such a logistic strategy, if rigorously applied, would surely have
defeated Alexander’s invasion in a country that had only intermittent areas of intensive cultivation.
And Persian command of the sea would have prevented Alexander from carrying food from Greece across the Aegean to supply his army.
In addition, the Persians had used such a logistic strategy earlier during the Plataea campaign.
Instead of assaulting the enemy’s army to defeat a Greek advance, Mardonius, the shrewd Persian commander, had used his superb cavalry to raid the Greek army’s supply lines to compel a retreat from its strong position at Plataea. The cavalry had intercepted some supplies, but then a
detachment of cavalry sent to the Greek rear “came upon a body Of 500 pack animals which were just entering the plain, bringing provisions to the Greek camp... Seeing this prey in their power, the Persians set upon them and slaughtered them, sparing none, neither man nor beast; till at last, when they had had enough of slaying, they secured such as were left and bore them off” to the Persian camp. This augmented an already plentiful Persian supply, for in nearby Thebes the Persians had
“abundant stores of corn for themselves, and of fodder for their beasts of burden.”
Able to interdict the supply line of the stationary Greek army, the Persian cavalry also gained temporary control of the spring that furnished water to much of the Greek army, leaving it “choked up and spoiled.” The Greek army found their supply situation desperate, for, in addition to a lack of water, “all the provisions they had brought with them were gone; and the attendants who had been sent to fetch supplies ... were prevented from returning to camp by the Persian horse, which now closed the passage.”
Yet even with this background and the advice of the leader of the Greek infantry, the Persian conference rejected a logistic strategy, the governor of the area closest to Alexander’s army asserting that “he would not allow a single house belonging to the people placed under his rule to be burned.”
So the Persian conference chose the combat strategy, their army contesting Alexander’s advance soon after he crossed into Asia. They lost their defensive battle on the Granicus River when the Companion cavalry defeated the Persian general-purpose cavalry and then attacked their Greek heavy infantry in the flank and rear; the conflict cost the Persians heavily, in both killed and prisoners among their infantry. This attrition together with the psychological impact of the defeat meant that no Persian field army contested Alexander’s advance through Anatolia. Meanwhile, in Mesopotamia, Darius III began creating a new army.
In carrying out his invasion, Alexander had no choice but combat strategy, for he had no means of attacking the logistics of the Persian army. But he did have an alternative in dealing with the splendid Persian fleet that effectively interdicted most Macedonian trans-Aegean sea traffic.
“Notwithstanding their superiority,” Alexander’s principal subordinate, the wise and experienced
Parmenio, “advised Alexander to fight a sea-battle, expecting the Greeks to be victorious with their fleet... He also urged that if they won the battle, they would reap a great advantage from it in regard to their main object in the war; and if they were beaten, their defeat would not be of any great moment; for even as it was, the Persians held the sovereignty of the sea.” Alexander argued that he did not want to give up on so “unstable an element” as the sea “the advantage which the
Macedonians derived from their skill and courage.” But he stressed the political consequences of defeat in a naval battle that would do “no small damage to their first prestige in the war, both for other reasons, and especially because the Greeks, being animated with courage at the news of the naval defeat, would attempt to effect a revolution” against Macedonian dominance of Greece.
But Alexander had a logistic alternative to combat; he could “get the mastery over the Persian fleet by defeating their army on land.” Alexander explained that he would be able to break up the Persian fleet “if he captured their maritime cities; since they would neither have any ports from which they could recruit their crews, nor any harbour in Asia to which they could bring their ships.” Initially, this strategy fitted his own logistic need to follow the fertile Anatolian coast and to keep in touch with his supply ships moving along the coast.
This line of advance also had an important political advantage, for the coast had a mostly Greek population, one often in revolt against Persian authority. Since Alexander represented a federation of Greek states, the Greek cities of Anatolia found it easy to yield to him. Alexander had counted on finding such a substantial political base for his conquest, knowing that this was fundamental to his success. Had Alexander faced the united political opposition of the subjects of the Persian King, his military victory on the Granicus would have availed him nothing, for, in spite of the substantial size of his army, he could not possibly have dominated so large a hostile country. But the Greek cities surrendered to him as he advanced, and he, acting as their liberator from Persian rule, appointed politically acceptable governors, usually from the cities and regions that surrendered to him.
Alexander’s invasion shows the importance of two variables in implementing the persisting strategy of territorial conquest. If Alexander had brought his huge army into a small state, such as one of those in Greece, he would have had such a high ratio of force to space as to render a popular resistance impossible. But even in the Anatolian provinces of the Persian Empire, he would have lacked the men to subdue and hold in subjection such a large country had he faced real political opposition. He succeeded because of the political support he found there and that he cultivated carefully and shrewdly.
Alexander’s accomplishment illustrates the important role of political attitudes and of fostering them, but the experience of Antiochus VII of Syria exhibits this factor even more graphically. In 130 B.C. Antiochus marched into Mesopotamia to recover territory recently conquered by Parthian invaders from the East. Having defeated the Parthians in the field and receiving a welcome from the cities Greek in culture and by many others dissatisfied with Parthian rule, Antiochus conquered Mesopotamia in a single campaign and drove the Parthian monarch back into his own domains. To secure his conquest, Antiochus wintered in his conquered territories, distributing his army and quartering it in a number of cities. But the burden of supporting the troops and their repellent behaviour alienated these cities from Antiochus, and they began to yearn for a return of Parthian rule. Meanwhile, King Antiochus apparently spent the winter very convivially rather than attending to his duties as commander. Parthian agents managed to arrange for the people of the cities where Antiochus had quartered his troops to make a simultaneous attack on the soldiers, and at the same time the Parthian army took the field early, finding supplies and support in a land that had recently welcomed Antiochus. The Parthians killed Antiochus, and they and the inhabitants of the cities captured most of his surprised army.
Most of the non-Greek areas of the Persian Empire also yielded to the firm but magnanimous Alexander. But because of the moderation and political astuteness of Alexander’s rule, they did not turn against him, as did Antiochus’ supporters. The Macedonian King could take advantage of a favourable political situation in that for more than half a century the Persian empire had displayed marked centripetal tendencies with frequent revolts led by the local rulers, called satraps. Only with difficulty and frequent conflict had the Kings maintained their authority over the whole of the empire. Darius III had ruled for only two years and as yet lacked established authority and prestige, if only because he came from a distant branch of the royal family and had come to the throne by the assassination of his two predecessors. Alexander exploited this political situation and usually secured the submission of most satrapies even before he crossed their borders. Wisely, he then carefully conserved vested interests, often confirming in power the Persian satrap who had yielded to him.
Even without this political weakness of the central government, local authorities would have found it difficult to make a strong resistance after Alexander had defeated the Persian army. Unlike the Greeks, Persian cities and provinces lacked a militia. Most of the non-Greek citizens of the empire had no tradition of or training for military service, having long relied on the professional forces of the King and the satrap. If local authorities had strongly opposed Alexander, lacking a militia to defend their walled cities they would have had to abandon a defensive persisting strategy of seeking to keep Alexander out of their domains. Instead, they would have had to resort to a defensive raiding strategy of harrying Alexander’s army. Alexander would face this kind of opposition later in the course of his long conquest.
After Alexander had conquered western and central Anatolia, he advanced along the coast toward Syria. Here in early fall Darius III, a capable soldier, marched to meet him and, arriving from Babylon with his army, took up a position in north-western Syria on the flank of Alexander’s advance down the Syrian coast. The Persian army occupied a well-watered position in a fertile plain where the King could easily supply his army and where, if a battle developed, he would have ample space for employing his numerically dominant cavalry. Darius’s army occupied a flank position, one where he could reach the enemy’s rear if Alexander marched past him down the Syrian coast.
But instead of attacking, Alexander waited, moving his army back and forth to find food and
relying also on supply by ship. As Alexander anticipated, Darius’s large army rapidly consumed the provisions in his vicinity, forcing him either to advance or retreat. But just as Alexander’s delay had exhausted Darius’s supplies and the King moved his army forward to the coast, Alexander held a council of war and, not knowing of Darius’s move, decided to advance with his army down the coast. Thus it worked out that in spite of Alexander’s astute delay, Darius’s army reached the coast in Alexander’s rear where the Persian army had a line of retreat into Syria while blocking the withdrawal of the Macedonians.
Darius’s army had occupied what is called a flank position, in which an army blocks an enemy’s advance by its ability to move into the rear of the enemy army should it march past. Alexander did not attack the Persian force in its flank position, disposed on a plain that provided admirable terrain for the action of the numerous and excellent Persian cavalry. Instead, he resorted to the logistic strategy of delay, so that a shortage of supplies would force Darius out of his flank position.
Though Alexander did not realise it, his logistic strategy worked when Darius had to move his army forward. Preferring, apparently, to fight Darius on the coast rather than the plain, Alexander marched past while Darius’s move forward executed the threat implicit in the flank position by moving into Alexander’s rear, blocking his route back to Anatolia.
Since Alexander’s army lived on the country and relied on coastal shipping for some supplies, Darius’s position in Its rear did not cut its communications. But this location did open Anatolia to
the Persians, threatening the Macedonian conquests already made and presenting the possibility of turning Alexander’s invasion into a raid in which he passed through the country but did not control it. So Alexander could not readily ignore Darius and continue his march south, and he could accomplish nothing by seeking to march around the Persians back into Anatolia. Thus, Alexander had to face Darius’s army, a confrontation he hardly dreaded. But the Persian move to Alexander’s rear had given Darius the advantage of the tactical defensive in the battle he must fight to save his crumbling empire.
To attempt to deal with the enemy army by a logistic strategy would work against Alexander’s large force in the narrow valley just as effectively as it would against the Persian’s. So Alexander immediately chose the combat alternative and marched north to attack Darius on constricted terrain that provided less scope for the action of the formidable Persian cavalry. But Darius made the most of the advantages of the tactical defensive given him by his move from his flank position into Alexander’s rear. The Persian King placed his army behind a stream, strengthening his front with some field fortifications, and concentrated his cavalry near the coast on the only open ground. But the tactical ascendancy of Alexander’s heavy cavalry and his sophisticated combination of the four weapon systems decided the battle. The Macedonian victory in the Battle of Issus, inflicting heavy losses on the Persians in both manpower and prestige, opened to Alexander the remaining
Mediterranean provinces of the empire, including Egypt. These Alexander proceeded to occupy.
In choosing to conquer Persian territory instead of conducting a strategic pursuit of Darius into Mesopotamia, Alexander remained true to his logistic strategy of defeating the Persian fleet by depriving it of its bases. For this reason he spent seven months of the winter and spring of the following year besieging and finally capturing the important city and naval base of Tyre, thus striking successfully at the Phoenician coast and the heart of Persian sea power. By delaying until the following summer his invasion of Mesopotamia, Alexander had fully conquered and organised his rear before he moved forward on the next stage of his conquest during the best campaigning season. And this campaign followed the model of its predecessors, Alexander winning another major tactical victory at the Battle of Arbela, conquering Mesopotamia, and sending Darius fleeing into the easternmost portion of his empire.
The night before the Battle of Arbela, the confident Alexander slept so well that when his generals had trouble awakening him in the morning, one “asked him how it was possible, when he was to fight the most important battle of all, he could sleep as if he were already victorious. ‘And are we not so indeed,’ replied Alexander, smiling, ‘since we are at last relieved from the trouble of wandering in pursuit of Darius through a wide and wasted country, hoping in vain that he would fight us’” Of course, the King overestimated Darius’s political strength and so the alternatives open to the Persian, but easily saw the problems presented by his comparatively small force in the
immense space still remaining in the Persian empire and the consequent difficulty of forcing battle on an unwilling opponent.
After defeating Darius at Arbela, Alexander again pushed eastward, receiving the submission of most of the Persian provincial satraps. Alexander claimed, by his defeat of Darius, the crown of the Persian Empire for himself, treated the defeated Persians with mercy and respect, and even began wearing clothing of the Persian style. These measures helped reconcile Persian officials to his rule as did the murder of the fleeing Darius by Bessus, one of his own subordinates, who then
proclaimed himself King. Alexander’s advance brought the country under his control, and he usually continued in office the satraps who surrendered to him. His conquest had paid for his war and had provided ample resources to continue it by the capture of the Persian treasury, 7,190 tons of gold and silver. Back