As I write this, American soldiers are involved in the fighting to retake the Iraqi city of Mosul from ISIS. This is the second time American troops have fought in a major engagement here: just a dozen years ago, the Marines maintained a large helicopter base there.
The city, normally home to two million people, is located along the Tigris River in northern Iraq, is situated on the key transportation routes connecting Syria, Turkey, and Iraq, and it is very close to Iraq’s northern oil fields. Beyond all that, the city has a rich history—a history that includes one of the most important battles in history and one that decided the future of Western Civilization—the Battle of Gaugamela.
Philip II of Macedon trained a magnificent army, but was killed before he could put it to work on its greatest challenge—the planned invasion of Persia. His son, Alexander, took the army and marched east to confront Persia, a far larger and more powerful nation, that was threatening to invade Greece and expand its territory into what is present-day Europe.
As Alexander left Greece, he left half of his army behind to secure his base there. There would be no revolts while he was busy conquering the world.
Alexander’s opponent in Asia was Darius III, who had ascended to the throne of Persia in 336 B.C.—the very same year that Alexander himself had become king in Macedon. As with most Persian successions, Darius had faced challenges—mostly from his own family—but by the end of 335 B.C. he was secure on his throne and could devote his full attention to the threat from the west and his dream of expansion.
That threat materialized when Alexander crossed into Asia in the spring of 334 B.C. The reported size of Alexander’s expeditionary force varies among ancient sources, but he probably had a fighting force of about 35,000 men. Of these, the best were the 1,800 Macedonian cavalry, called The Companions, who were fiercely loyal to the young king.
Alexander’s army was a formidable, flexible, integrated force, and was already well-practiced in the art of slaughtering its opponents. The Persians did not realize it yet, but they were in serious trouble.
When Alexander crossed into Asia in the spring 334 B.C., he jumped from his boat and speared the ground in a symbolic act of claim by conquest. He also visited Troy and honored his legendary ancestor, Achilles. Now that the religious matters had been seen to, Alexander took his army inland: the great adventure had begun.
Some of the Persian leaders urged Darius to not confront Alexander immediately, but to retreat eastward to draw Alexander away from the coast, while simultaneously destroying the farmlands and the food warehouses in front of the Macedonian army. Had Darius employed this strategy, a few history books would have a small footnote about an obscure military leader named, "Alexander the Schmuck". However...
The two armies met at Granicus, beside the Mediterranean, in what today would be northern Syria. Despite being outnumbered, Alexander was quickly victorious, slaughtering the Persian force. The Persians had relied on mercenaries for the battle and had badly underestimated Alexander's abilities. Darius would not make the same mistake twice.
The exact size of the Persian army is not known, since every writer in the last two millennia has (in the interest of a good story, of course), exaggerated the size of the losing army while minimizing the size of the victors. One source—probably the distant ancestor of Baghdad Bob—put the size of the Persian Army at 600,000. A more credible number is about 100,000 (including many tens of thousands of Persian cavalry).
Darius decided to refight the battle of Granicus at Issus, but even with a larger force, this was a foolish mistake. (In all fairness, Darius had not been present at Granicus, so we cannot judge him quite so harshly.) He maneuvered his large army onto a narrow strip of land that was bordered by the sea on one side and mountains of the other. The overly confident Darius waited for Alexander, who once again used his superior cavalry to cut through the Persian Army, sending the Persians into flight.
So complete was Alexander’s victory that he even captured Darius’ baggage train with its huge sums of money, Darius’ wife and son, and the Royal Mother! The Battle of Issus handed the entire western half of the Persian Empire to Alexander, but the big battle for the whole of Persia was still ahead.
In the months after Issus, Darius sent a series of letters and embassies to Alexander seeking some sort of a negotiated settlement on increasingly generous terms. The story goes that when he finally offered to cede Persian holdings west of the Euphrates, along with a vast ransom for his still-captive family, Alexander’s closest confident and commander of the remainder of the cavalry, Parmenio, commented, “If I were Alexander, I would accept that offer,” to which Alexander replied, “If I were Parmenio, I would too. But I am Alexander.” So the king responded to Darius in the most arrogant terms. He already owned the territories west of the Euphrates and he’d be coming for the rest soon enough.
For two years, Alexander busied himself subduing today's Syria and Egypt, while Darius raised yet another army. Denied the resources of his western empire, Darius had assembled an army from the eastern sectors of his realm. Once again, we aren’t certain of the size—one contemporary reported it as an even million infantry with almost half that many cavalry—but there can be no doubt that it was at least as big as the army at the previous battle, if not larger. Hazarding a conservative guess, we may imagine it as over 100,000 strong, with perhaps 40,000 of that total being cavalry.
In addition, Darius had 200 scythed chariots, a most mysterious but evidently fearsome-looking contraption—we aren’t sure what they looked like—and probably very effective against peasant armies. However, these vehicles were far less effective against disciplined ranks of infantry.
The real strength of Darius’ army lay in its cavalry. Darius sent scouts ahead to find suitable ground and a site was chosen at Gaugamela, not far from modem Mosul in Northern Iraq. Darius deployed his troops with hills behind him and a plain in front of him, and made sure the plain was perfect for his chariots. Entrenched, the Great King waited for Alexander to accept his challenge and while he waited, he had his forces smooth out the ground of the plain for those chariots.
Alexander made his way into Northern Mesopotamia and, since it was no secret where Darius and his huge army were located, directed his army to meet the Great King and his troops without too much trouble. The march from Egypt took the best part of four months. At 9:00 a.m. the twentieth of September 331 B.C., there was an eclipse of the moon, which was noted by the Macedonians the night before they left the banks of the Tigris to meet Darius. Since it is recorded that eleven days elapsed between the eclipse and the battle, we can date Gaugamela precisely to the first of October 331 B.C. On that single and remarkable day, the fate of the largest land empire yet seen on earth was decided.
For an ancient battle, while Gaugamela is exceptionally well documented, we still wish there were more detail of exactly what happened. Four different writers recorded what happened, but they were limited to reporting what happened in their individual area of the battle. Partly because of the huge dust cloud generated, and partly because of the natural fog of war, their accounts are limited, but the general course of the battle is known.
Alexander drew up his army in the standard formation with his Greek phalanxes and the infantry in the center, with Parmenio and the allied cavalry on the left, and with Alexander, himself, at the head of his Companions on the right. However, there were two changes to this standard formation: first, a second phalanx of Greek allies and mercenaries was drawn up behind and parallel to the main phalanx. Second, light-armed and cavalry detachments were stationed on the extreme left and right of the forward formation, but moved back slightly to guard the flanks and cover the gap between the two phalanxes. These troops were positioned for defense, since Alexander expected the larger Persian force to flank his force on both sides—ordinarily a sure sign of an imminent military disaster.
As it advanced, Alexander’s army moved toward the right, where the Persian overlap was most pronounced. Now this may have been an intentional move, intended to generate uncertainty among the Persians and a probe for weaknesses, or it could have been an error. Whatever the case, the rightward shift worked wonders for Alexander. Darius opened by sending his scythed chariots and some of the cavalry units into action, but these had no real effect. The skirmishers on Alexander's side handled the chariots easily enough, mostly by killing their horses. (You never see this in the movies, but if you really want to stop that stagecoach—shoot the lead horse. The whole contraption will go ass over teacups—a technical term, of course.)
In the face of the rightward shift of the Macedonian army, a gap opened between the Persian center and its left wing, which was wheeling around in the anticipated flanking movement. Alexander and his Companions were perfectly placed on the right to take advantage of this gap, and wedged the cavalry relentlessly into this gap, assailing the wings of the Persian center and left and pushing to get to the rear to reach Darius himself, who retreated. The phalanx now engaged the Persian center and began its terrifying work of butchery. Gaugamela was, in the end, a classic hammer-and-anvil battle, with the Persians pinned by the phalanx while the cavalry drove to the rear.
On the left, Parmenio’s job was merely to hold his command and prevent the Persians from getting in behind the Macedonian line. But he was under immense pressure. Pinned down, a gap appeared in the Macedonian line to the right of Parmenio’s position as the phalanx moved up to engage the Persians—a gap, in fact, almost identical to the one that had appeared in the Persian line. Indeed, some Persian cavalry drove through this gap, but uselessly attacked the Macedonian camp, before the reserve phalanx moved up to neutralize them.
Darius fled in fear for his life, only to be murdered by one of his own generals the following summer. Alexander went on, of course, to conquer the rest of the Persian Empire.
Alexander’s victory at Gaugamela gave him the Persian throne. The two main sources of that victory were his driving charge into the gap on the Persian right and Parmenio’s superb holding action on the left. Had either failed, the outcome of the day would have been very different.
This was clearly a turning point in history: had Darius won, he undoubtedly would have expanded his empire into present day Europe, well before the rise of the Roman Empire. The modern world might have looked very different had he succeeded.
Alexander probably should have stopped and consolidated his gains, but he continued eastward. A less powerful Persian Empire would eventually rise after his death, but by then the Roman Empire would have replaced the Macedonians as the great power in the West.
Once again, we are at Mosul, and once again, we are fighting an eastern force threatening to overrun Europe. I leave it to you whether we have anyone even faintly resembling modern-day equivalents of either Darius or Alexander--and who that might be.