In the final part of our series on the Wars of the Persians and Macedonians, we will focus on Alexander the Great's invasion of Persia and the reasons for his success.
The invasion of Alexander the great was rather more successful than that of his father, defeating Darius’ Anatolian Satraps at the Granicus river and then defeating the king himself at Issus. Following this victory, much of the western provinces capitulated, allowing Alexander to enter the upper Satrapies where he defeated Darius again at Gaugamela. Darius was assassinated shortly after, resulting in the collapse of the Achaemenid state, and Alexander spent the next five years cementing his rule over the former imperial territories. This raises the question: why was Alexander so successful in his campaigns?
The classical sources offer a number of answers to this question the most commonly postulated, being that of Persian military incompetence. The Macedonian military is often referred to as being far superior – or at least better equipped – to that of the Persians for example. However, an examination of the battles narrated by these same authors provides a contradictory picture. In both major battles, at Issus and Gaugamela, the Macedonian phalanx failed to breach, or even force back, the Persian Kardaka (indeed, at Issus, the reverse nearly occurred). Rather, the victories occurred following breakthroughs on the flanks as a result of cavalry engagements.
The Persian cavalry was, by 333 BC, a general shock force, possessing superior armour and weaponry than their Macedonian counterparts, who were lightly armed and consequently, far more manoeuvrable. The companions were also a far more specialised and seemingly disciplined unit. These factors enabled the Macedonians to exploit breaches far more successfully than the Persians (who successfully broke the Macedonian lines first at Gaugamela but became distracted looting the Macedonian baggage train and therefore failed to encircle Parmenion’s flank).
Another factor to consider is the quality of the generals under each monarch. Alexander’s army was at this time lead by the established veterans of Philip II campaigns; Parmenion and his family, Antigonus, Egyrius and Cleitus are good examples. Alexander’s ‘new men’ had yet to accede to prominence. These were men like Seleucus, who would later exceed perhaps even Alexander’s achievements, but at the time the effectiveness of the Macedonian suffered from the loss of Philip’s veterans – Alexander’s continuing victories more the result of superior numbers (Hydaspes) or lack of coherence on the part of the enemy (Bactria/Sogdiana).
On the Persian side, however, most of the notable generals of Artaxerxes’ reign with the exception of Darius himself, were dead by 334 BC (Bagoas, Mithridates, Mentor of Rhodes, and Arsites among others). This lack of veteran commanders was further exacerbated by the ongoing Anatolian front, where those commanders from the battle of Issus launched an almost successful counterattack against the Macedonians led by Antigonus. This theatre of the conflict continued from 334 until 322 and Perdikkas’ conquest of Cappadocia and tied down many of Darius’ best troops and commanders. This helps explains the comparative lack of discipline among the Persians and the strategic tardiness that cost them the battle of Gaugamela.
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