The Battle of Issus was a significant victory for Alexander the Great in his conquest of the Persian Empire.

Following his invasion of the Persian Empire in the spring of 334 b.c.e., Alexander the Great won an important battle at the Granicus River, in Asia Minor, against a Persian force of comparable size. This victory permitted Alexander to liberate the Greek city-states of Anatolia and to neutralize the Persian navy through the capture of key ports and bases in the Levant. Alexander the Great
Darius III

The need to entirely deny the Persian fleet portage along the eastern Mediterranean Sea compelled Alexander to move his army from Asia Minor southeastward toward the Syrian coast in the autumn of 333 b.c.e. This action would ultimately bring the Greco-Macedonian army into direct confrontation with a numerically superior Persian force advancing northward from the Euphrates River under the command of the Persian king, Darius III.

As the Greek army continued its southward march into Syria along the coastal road toward the settlement of Myriandros, the Persian army advanced northward through a more difficult eastern mountain pass called the Amanian Gates, which crossed Mount Amanus, near the plain of Issus. By these movements, the two armies unknowingly passed one another.

On learning that Darius was behind his position, Alexander turned his army north so as to intercept the Persian host before it could escape the confines of the coastal hill country. Near the village of Issus on the Gulf of Iskenderun and north of the settlement of Myriandros, the two armies met. The battle developed on a small coastal plain, forcing both armies to deploy according to the geographical constraints of the space available. Movement was further hampered by the Pinarus River, whose course effectively divided the battlefield. Dominating the plain to the east was Mount Amanus.

Alexander’s battle line stretched the length of the plain, forcing the Macedonian king to anchor the army’s left wing on the shoreline of the Iskenderun and its right near the Amanic foothills. Thessalian, Peloponnesian, and other allied cavalry were then deployed on the left flank, with a second force of cavalry, including the Companions, positioned on the right. Elements of light and heavy infantry were placed in support of these forces or held in reserve, with the Macedonian phalanx securing the center.

A damaged rendering of the Battle of Issus.

(Library of Congress)

On the approach of the Greek army, Darius temporarily dispatched a sizable force of cavalry and light infantry south across the Pinarus River to serve as a protective screen while the remainder of the army arrayed for battle on the north bank of the river. Fully deployed, the Persian front line ranged the full length of the Greek formation and beyond. On the left, units of light infantry extended into the Amanic foothills, where they threatened to turn Alexander’s extreme right flank. At the center of Darius’s main vanguard was a large concentration of some thirty thousand Greek mercenaries, flanked by divisions of Persian heavy infantry called Kardakes. Arrayed behind this front was a sizable reserve of light and heavy infantry. On the extreme right, opposite the Greek allied cavalry, Darius stationed a large contingent of Persian horses. Though the Persian army was formidably arrayed, the narrowness of the plain of Issus neutralized the numerical advantage of the larger force and handicapped any effort by Darius to use his superior numbers of cavalry to best effect against the Macedonian formations.

Alexander sought to check the threat posed by the Persian forces on the high ground to the east by ordering a mixed contingent of archers and cavalry to form a salient on his right. Elements of this reconstituted force then launched an assault that quickly scattered the Persians on the foothills. Following this skirmish, Alexander briefly rested his army before initiating the primary attack against the Persian host.

Alexander opened the main battle with an intense cavalry charge that immediately shattered the Persian left wing. Advancing to the attack, the Macedonian phalanx crossed the shallow Pinarus but was stalled by the steepness of the opposing bank and the stiff resistance of the Greek mercenaries. As the phalanx continued to press its assault, the cohesion of the Macedonian front weakened, exposing gaps in the line, which the Greeks exploited to full advantage. The result was a violent struggle of heavy infantry that, for a time, left the outcome of the engagement in question. Pressure on the phalanx was finally relieved when Alexander, fresh from his victory on the right, outflanked the remnants of the Persian left and delivered a flank attack that crumpled the mercenary formation. As the Persian center began to disintegrate, Alexander wheeled the remainder of his force to the left in order to drive against Darius’s position in the center. This charge unnerved the Persian king, who turned his war-chariot and fled the field.

Simultaneous with these events, the Persian cavalry, on the north bank of the Pinarus River near its juncture with the Gulf of Iskenderun, having witnessed Alexander’s charge on the left, launched a massive charge that threatened to overwhelm the squadrons of Thessalian horses deployed near the shoreline. The momentum of this assault was checked only when the king was seen to flee the battlefield following the destruction of the Persian left and center. What followed was a complete rout of the entire Persian army, followed by a sustained pursuit by the forces of Alexander.

The Battle of Issus was instrumental in breaking Persian power in the eastern Mediterranean. After the engagement, Darius III proposed a treaty of friendship and alliance between the two kingdoms, offering Alexander control of all Persian territories west of the Euphrates River. The Macedonian king’s rejection ultimately precipitated the Persian army’s stunning defeat at Gaugamela in 331 b.c.e. This latter engagement ensured Alexander control of the Persian crown.

• Arrian. History of Alexander and Indica. Translated by P. A. Brunt. Cambridge, Mass.: Harvard University Press, 1976-1983. An account by an ancient historian, writing four hundred years later, of the exploits of Alexander the Great.
• Bosworth, A. Brian. Conquest and Empire: The Reign of Alexander the Great. New York: Cambridge University Press, 1988. Bosworth relates the story of how Alexander the Great built his empire.
• Curtius, Quintus. The History of Alexander. Translated by John Yardley. New York: Viking Penguin, 1984. A examination of the life of Alexander the Great.
• Dodge, Theodore Ayrault. Alexander. London: Greenhill Books, 1993. A biography of Alexander the Great, with reference to the Battle of Issus.

Alexander the Great; Philip II of Macedonia. Issus, Battle of (333 b.c.e.)