Battle of the Granicus The Battle of the Granicus River in May 334 BC was the first of three major battles fought between Alexander the Great and the Persian Empire . Fought in Northwestern Asia Minor , near the site of Troy , it was here that Alexander defeated the forces of the Persian satraps of Asia Minor , including a large force of Greek mercenaries led by Memnon of Rhodes . The battle took place on the road from Abydos to Dascylium ( near modern day Ergili , Turkey ) , at the crossing of the Granicus River ( modern day " Biga Çayı " ) . Background . Following the assassination of Alexander ' s father , Philip II of Macedon , and the subsequent consolidation of Alexander ' s Macedonian positions , he set out into Asia in 334 BC . After the death of Phillip of Macedon , many cities and civilizations that he had conquered wanted to rebel because they wanted justice and their freedom back . These nations included the Illyrarians , Thractionians , and Greeks . Alexander noticed their desire to gain their independence and had to react quickly before they got their chance to do so . After controlling his conquered nations and getting everything set in Macedonia , Alexander started to prepare for his next major conquest : the invasion of Asia . Before the Battle of Granicus , Alexander appointed his father ’ s experienced general Antipater as regent in his absence from Macedonia . In the spring of 334 B . C , Alexander was the man in control of an army of 13 , 000 infantry and 5 , 100 cavalry . He and his army went on a 20 - day march from Macedon to Hellespont . Deployment of Persian troops . Before Alexander and his army were able to cross at Hellespont , the Persian provincial governors and others in power assembled their forces of 10 , 000 cavalry and 5 , 000 infantry to the town of Zelea . Memnon was a high - ranking Greek mercenary that was on the Persian side , tried to devise a plan to attack against Alexander . Memnon told the Persian army to basically destroy their means of food and production in the villages that Alexander would have to pass . This would then make it harder for Alexander and his army to survive on their long journey before the battle . The satraps did not trust Memnon because of his nationality and did not destroy their territories . The Persians had two major objectives ; first they would try to force Alexander toward a chosen position before he could continue on inland , second the Persians hoped to be able to be in a defensive position that would minimize his advantage ( in infantry ) . The Persians advanced from Zelea to Granicus River which would be an obstacle for Alexander and his army . His army would not be able to hold formation , which was Alexander ’ s strategic point . The Persians awaited the arrival of the Macedonians with all their cavalry in the front line . The battle . According to Alexander ' s biographer Arrian , Alexander ' s army met the Persians on the third day of May from Abydos . Alexander ' s second - in - command , Parmenion suggested crossing the river upstream and attacking at dawn the next day , but Alexander attacked immediately . This tactic caught the Persians off guard . The Macedonian line was arrayed with the heavy Phalanx es in the middle , and cavalry on either side . Alexander was with the Companions on the right flank . The Persians expected the main assault to come from Alexander ' s position and moved units from their center to that flank . The battle started with a cavalry and light infantry feint from the Macedonian left , from Parmenion ' s side of the battle line . The cavalry squadron was led by the officer Ptolemy , son of Philip . The Persians heavily reinforced that side , and the feint was driven back , but at that point , Alexander led the horse companions in their classic wedge - shaped charge , and smashed into the center of the Persian line . The Persians countercharged with a squadron of nobles on horse , and accounts show that in the melee , several high - ranking Persian nobles were killed by Alexander himself or his bodyguards , although Alexander was stunned by an axe - blow from a Persian nobleman named Spithridates . Before the noble could deal a death - blow , however , he was himself killed by Cleitus the Black . Alexander quickly recovered . The Greek cavalry then turned left and started rolling up the Persian cavalry , which was engaged with the left side of the Macedonian line after a general advance . A hole opened in the recently vacated place in the battle line , and the Macedonian infantry charged through to engage the poor - quality Persian infantry in the rear . At this , and with many of their leaders already dead , both flanks of the Persian cavalry retreated , seeing the collapse of the center . The infantry routed too , many being cut down as they fled . Total casualties for the Greeks were between 300 and 400 . The Persians had roughly 1 , 000 cavalry and 3 , 000 infantry killed , mostly in the rout . The Greek mercenaries , under the command of Memnon of Rhodes , who fought for the Persians , were abandoned after the cavalry retreat . They attempted to broker a peace with Alexander but to no avail . As a result , after the battle Alexander ordered his infantry , who until this point had played no role in the battle , to slaughter the mercenaries to a man . 18 , 000 mercenaries were killed and 2 , 000 enslaved and sent back to Macedonia in chains for hard labour . It is believed that Alexander had a strong majority of the mercenaries killed in fear of . Also , Alexander sent 300 Persian armour s to the Parthenon of Athens as an oblation to Athena , with this epigram : " " Alexander , son of Philipp , and the Greeks , except of Lacedaemonians , from the barbarians who live in Asia " " . ( « Ἀλέξανδρος Φιλίππου καὶ οἱ Ἕλληνες , πλὴν Λακεδαιμονίων , ἀπὸ τῶν βαρβάρων τῶν τὴν Ἀσίαν κατοικούντων » - " Alexandros Philippou kai hoi Hellēnes plēn Lakedaimoniōn apo tōn barbarōn tōn tēn Asian katoikountōn " ) . That account of the battle is directly contradicted by Diodorus Siculus who states " When Alexander learned of the concentration of the Persian forces , he advanced rapidly and encamped opposite the enemy , so that the Granicus flowed between the encampments . The Persians , resting on high ground , made no move , intending to fall upon the foes as he crossed the river , for they supposed they could easily carry the day when the Macedonian phalanx was divided . But Alexander at dawn boldly brought his army across the river and deployed in good order before they could stop him . In return , they posted their mass of horsemen all along the front of the Macedonians since they had decided to press the battle with these . Memnon of Rhodes and satrap Arsamenes held the left wing each with his own cavalry ; Arsites was stationed next with the horsemen from Paphlagonia ; then came Spithrobates satrap of Ionia at the head of the Hyrcanian cavalry . The right wing was held by a thousand Medes and two thousand horsemen with Rheomithres as well as Bactrians of like number . Other national contingents occupied the centre , numerous and picked for their valour . In all , the cavalry amounted to more than ten thousand . The Persian foot soldiers were not fewer than one hundred thousand , but they were posted behind the line and did not advance since the cavalry was thought to be sufficient to crush the Macedonians . " The record of Arrian and Diodorus on the battle of Granicus can ' t be reconciled so historians usually prefer Arrian , although some revisionists try to reconcile the two accounts . Revisionist view . Historian Peter Green , in his 1974 book " Alexander of Macedon " , proposed a way to reconcile the account of Diodorus and Arrian . According to Green ' s interpretation , the riverbank was guarded by infantry , not cavalry , and Alexander ' s forces sustained heavy losses in the initial attempt to cross the river and were forced to retire . Alexander then grudgingly accepted Parmenion ' s advice and crossed the river during the night in an uncontested location , and fought the battle at dawn the next day . The Persian army hurried to the location of Alexander ' s crossing , with the cavalry reaching the scene of the battle first before the slower infantry , and then the battle continued largely as described by the Arrian and Plutarch accounts . Green accounts for the differences between his account and the ancient sources by suggesting that Alexander later covered up his initial failed crossing . Green devotes an entire appendix in support of his interpretation , taking the view that for political reasons , Alexander could not admit even a temporary defeat . Thus , the initial defeat was covered up by his propagandists by a very heroic ( and Homeric ) charge into the now well deployed enemy . Result . Towards the end of this battle , Alexander the Great captured and held the Greek mercenaries for slaves while forcing them to return to Macedonia . Memnon was able to escape but then died of disease on an island in the Aegean .