It's September of the year 331 BC. After taking Phoenicia and Egypt, Alexander marches east, to the inland of the Persian Empire. As his troops were about to cross the Tigris river, he received scout reports, that Persian King Darius had gathered another huge army and was preparing for a decisive encounter with the Macedonians. Both armies finally met on the vast open field near the village of Gaugamela in a final clash between two of the biggest powers of classical antiquity. It's beginning of the year 331 BC. After the successful subjugation of Tyre and Gaza, the Macedonian army took some time to regenerate in the rich valley of the Nile. The Egyptian satrap didn't try to oppose Alexander, as the Macedonian was seen as a liberator rather than an invader, since Egypt wasn't the most loyal of Persian provinces. After the crushing defeat near Issus, Persian King Darius changed his approach and tried to stop Alexander's extraordinary conquest by using diplomacy. Yet the Macedonian King refused Darius' increasingly generous terms thrice, and with winter passing by, he started to draw the plans for the upcoming Babylonian campaign. With all preparations completed, the refreshed and decently supplied Macedonian force marched out back to Phoenicia in the beginning of April. It's worth noting, that Alexander paid significant attention to the often overlooked logistical part of his conquests. Maintaining such a considerable force in excellent shape for many years far away from home required exceptional planning and stellar management. For as long as it was possible, the Macedonian army stuck to the coast, and utilized the fleet to take care of provisions. Darius was well informed of the Greek movement and by the time Alexander crossed the Euphratus, the new Persian army was being assembled. The King of Kings expected the Macedonians to march along the river, straight to Babylon, and decided to use scorched earth tactics by ordering the plunder of the Euphratus valley. But thriving cities lying close to the river were decently defended, making supply gathering quite challenging, so Alexander chose a northern route instead which, although longer, had rural settlements that offered easy access to food and water. Upon hearing the unexpected news, Darius instantly departed Babylon heading north, along the east bank of the Tigris River. He appointed a strong mounted unit under Mazaeus, governor of Babylon to guard the northern crossings of the Tigris and plunder its east bank, to hinder the Macedonian march. But Mazaeus failed to challenge the Greeks during the crossing, and in the middle of September Alexander reached the east side of the river. Darius knew, that the encounter was close, so he started to seek a suitable place for the upcoming battle. He setup camp on a wide plain near the village of Gaugamela and began preparations. In the meantime Alexander's troops caught a Persian scouting party and found out that Darius was camping 30 kilometres to the east. The Macedonian King quickly dispatched his own scouts and advanced towards the enemy. Camp was set behind a hill about 10 kilometres away from the presumed battlefield nd after a few days of rest, on the last days of September, Alexander departed towards the Persian positions. The hill between the two armies was guarded by Mazaeus' detachment, but upon seeing at whole Macedonian army was approaching, the Persian nobleman simply retreated without a fight and rode back to the camp, yielding the hill Having the hill was an advantage but Darius still held the open fields which suited combat for his larger army far better. So the hill was important, but an acceptable loss. Alexander took the hill and, after a short examination of the environs, decided to set a temporary camp there. This manoeuvre gave him a significant advantage, as the higher ground provided a good view of the Persian camp and their troop deployment. Moreover, the hill was well suited for defence purposes, so Alexander didn't rush and comfortably prepared for the battle, making sure his troops were well fed, rested and in good mental condition. In comparison, due to Mazaeus' failure, Darius was under constant threat of sudden Greek attack, even at night, so his troops had to maintain readiness for battle. Of course, Darius had superior numbers, plenty of solid cavalry and suitable terrain, but his army could do nothing but wait for the Macedonians to make the first move, as storming the ridge was not a viable option. The sun slowly set on the horizon, while Alexander discussed the upcoming battle with his officers. It is said, that his second-in-command, Parmenion, advised a night attack, in order to catch Persians off guard, but Alexander turned down this idea as too risky. The Macedonian command then agreed to attack the next day, in the morning. The night passed by, and the first sun rays lit up the battlefield. It was the 1st of October. The Persian army was already in battle formations, as they spent the whole night waiting for the Macedonian attack, which never came. Darius efficiently used the manpower of his vast empire, up to 100,000 men were gathered to fight for their king. 10,000 of the professional Immortal infantry together with a few thousand Greek mercenaries formed the core of the Persian centre. But the real power of Darius' army was positioned on the flanks. More than 30,000 fine cavalrymen from various Persian satrapies posed a serious threat, especially on such a wide and level battlefield. Darius also had a few hundred Indian scythed chariots and even fifteen elephants, though these animals probably didn't take part in the battle. The rest of his army was formed by various infantry units gathered from tribes inhabiting the Achaemenid Empire, though their battle potential was questionable. Due to the size of Persian army, the command was split between Darius, and his trusted generals - Mazaeus and Bessus. We could spend another five minutes discussing the exact positions of Bactrian cavalry or Parthian infantry in the Persian battle line, but, as in battle, time is of the essence and at this point, the sun was near noon. Oversleeping Alexander finally awoke, and the refreshed Macedonian army abandoned the hill, and began their deployment. 40,000 infantrymen and a 7,000 strong cavalry detachment formed a slanted battleline, with the right flank facing the front of the Persian centre. To avoid possible encirclement, both flanks were sufficiently reinforced and slightly curved backwards. The Macedonian center was occupied by a disciplined sarissa phalanx, supported by solid hypaspist units. Cavalry was split between both flanks, Thessalian units on the left, and Companion cavalry on the right. The second line was occupied by Thracian and Illirian infantry. Just like in previous battles, the command was split between Alexander and Parmenion. To achieve a flanking advantage, the Macedonian king started to move his line right, but Darius immediately countered by stretching his left flank and matched the opponent's movement. Darius had the battlefield levelled and cleared off any obstacles for more effective chariot use, which is why he wanted to prevent the Macedonians from leaving the prepared ground. Persian cavalry moved out and attacked Alexander's far right. Fierce fighting began, with no clear winner. But as time passed, Macedonian cavalry prevailed, and routed some of the Persian units, though suffering serious damage. Seeing the trouble on his left, Darius sent all of his scythed chariots to storm the Greek centre. Yet this attack wasn't particularly successful, as defenders opened their ranks and allowed attackers to ride through the line, raining javelins on them at the same time. Following the chariots, the Persian right flank led by Mazaeus stormed Parmenion's side, killing many Greeks in the process and forcing the Macedonian commander to give ground. Parmenion was in serious trouble, being outnumbered and partially enveloped, but it wasn't the first time he was forced to fight at unfavourable odds. His flank fought bravely, and somehow endured the Persian push, though at high cost. It was at this point that Darius noticed that Alexander was moving his flank to the right while Parmenion stayed on the left, creating a gap in the Macedonian centre. The Persian king saw this as a weak point and impulsively sent his Immortal units to exploit the opening. But, this was bait. Doing so exposed Darius’s own centre. Alexander had waited for such an opportunity, he swiftly moved Companion cavalry supported by the remaining units of his flank and struck the Persian centre, right where Darius' exposed royal guard stood. Despite the support of the second line units, the impetus of the Macedonian charge quickly broke the Persian line. Soon, Darius realised the danger and just as he did two years earlier, fled the battlefield. Alexander began pursuit immediately, but soon overturned his temptation and rode back to relieve Parmenion's flank. Fierce combat still raged on the Macedonian left, when rescue finally came, the remaining Persian forces were soon overwhelmed and routed. Although Darius managed to escape yet again, complicating Alexander's political plans to crown himself as the King of Persia, the military power of the Achaemenid Empire was crippled. Macedonians had the core cities of Mesopotamia and Persia at their fingertips. After the brilliant show of his strategic and tactical prowess near Gaugamela, Alexander effectively ended the hegemony of the powerful Persian Empire in less than five years, but its subjugation didn't satiate his lust for power and his story is yet to be continued.
