Battle of Heraclea The Battle of Heraclea took place in 280 BC between the Romans under the command of Consul Publius Valerius Laevinus and the combined forces of Greeks from Epirus , Tarentum , Thurii , Metapontum , and Heraclea under the command of King Pyrrhus of Epirus . Background . Tarentum was a Greek colony , part of Magna Graecia . The members of the leading faction in Tarentum , the democrats under Philocharis or Ainesias , were against Rome , because they knew that if the Romans entered Taranto the Greeks would lose their independence . The Greeks in Tarentum had grown afraid of Roman expansion after the Third Samnite War . After the surrender of the Samnites in 290 BC , the Romans founded many colonies in Apulia and Lucania , the most important of which was Venusia . In 282 BC , after a battle against the Samnites , Lucania ns , Bruttians and Thurii , Roman troops entered the Italian Greek colonies of Croton , Lokroi , and Rhegium . Democrats from Tarentum knew that as soon as Rome finished its war with the Gauls , Lucania ns , Etruscans , Samnites , and Bruttians , they would enter Tarentum . Another event that concerned the Tarentines was that the aristocratic faction of Thurii that had taken power had invited a Roman garrison into their city ; the Tarentines , who had been the referents of all the Magna Graecia colonies , were deeply worried about this fact . The second faction in Tarentum were the aristocrats , led by Agis , who did not oppose surrendering to Rome , as it would lead to the return of the aristocratic faction to power . The aristocrats , however , could not surrender directly and become unpopular with the population . In the autumn of 282 BC , Tarentum celebrated their festival of Dionysus ; while in their theatre in front of sea , they saw ten Roman ships , with soldiers and supplies for the Roman garrison of Thurii , entering the Gulf of Taranto . The Tarentines were angry , because the Romans had signed an agreement not to sail into the Gulf of Taranto , and they prepared their navy to attack the Roman ships . A few of the ships were sunk , and one was captured . The Tarentines knew that they had few chances of victory against Rome . They decided to call for help Pyrrhus , King of Epirus . The army and fleet of Taranto moved to Thurii and helped the democrats there exile the aristocrats . The Roman garrison placed in Thurii withdrew . The Romans sent a diplomatic mission to settle the matter and take back the prisoners but the negotiations ended abruptly , so Rome declared war on Tarentum . In 281 BC , Roman legions under the command of Lucius Aemilius Barbula entered Tarentum and plundered it . Tarentum , with Samnite and Salentinian reinforcements , then lost a battle against the Romans . After the battle the Greeks chose Agis to sign a truce and begin diplomatic talks . These talks were also broken off when 3 , 000 soldiers from Epirus under the command of Milon entered the town . The Roman consul withdrew and suffered losses from attacks by the Greek ships . Pyrrhus decided to help Tarentum because he was in debt to them — they had earlier helped him conquer the island of Corcyra . He also knew that he could count on help from the Samnites , Lucanians , Bruttians , and some Illyrian tribes . His ultimate goal was to re - conquer Macedon he had lost in 285 BC , but did not have enough money to recruit soldiers . He planned to help Tarentum , then go to Sicily and attack Carthage . After winning a war against Carthage and capturing south Italy he would have enough money to organise a strong army and capture Macedon . Preparation . Before he left Epirus , Pyrrhus formed an alliance and borrowed soldiers and money from the pretender to the Macedonian throne , Ptolemy Keraunos . His long - time friend and ally Ptolemy II Philadelphus , king of Ptolemaic Egypt , also promised to send 9 , 000 soldiers and 50 war elephant s . He also recruited horsemen from Thessaly and archers from Rhodes — as their rulers wanted to avoid a war with Epirus . In the spring of 280 BC Pyrrhus landed without losses in Italy . After hearing of Pyrrhus ' arrival in Italy the Romans mobilized eight legions with auxiliares , totalling about 80 , 000 soldiers . They divided it into four armies : Publius Laevinus moved towards Heraclea , a city founded by the Tarentines , with the intention of cutting Pyrrhus from the Greek colonies of Calabria , thus avoiding their uprising against Rome . Battle . Pyrrhus did not march against the Romans while he was waiting for his allies ' reinforcements . When he understood that reinforcements were not coming , he decided to fight the Romans on a plain near the river Siris ( modern Sinni ) , between Pandosia and Heraclea . Pyrrhus took up position there and waited . Before the fight he sent diplomats to the Roman consul , proposing that he could arbitrate the conflicts between Rome and the population of south Italy . He promised that his allies recognised him as a judge and demanded the same from the Romans . The Romans denied his request , and entered the plains on the right of the Siris river where they set up camp . It is unknown how many troops Pyrrhus had left in Tarentum , but he probably had about 25 - 35 , 000 troops with him at Heraclea . He took up position on left bank of the Siris , hoping that the Romans would have difficulty crossing the river , which would allow him more time to prepare his attack . He set up some light infantry units near the river to let him know when the Romans began to cross , and planned first to attack them with his cavalry and elephants . Valerius Laevinus had about 30 , 000 soldiers under his command , including many cavalry , peltasts , and spearmen . It would be the first time in history that two very different juggernauts of war clashed : the Roman Legion , and the Macedonian Phalanx . At dawn , the Romans started to cross the river Siris . The Roman cavalry attacked on the flanks the scouts and light infantry , who were forced to flee . When Pyrrhus learned that the Romans had begun crossing the river he led his Macedonian and Thessalian cavalry to attack the Roman cavalry . His infantry , with peltasts and archers and heavy infantry , began their march as well . The Epirote cavalry successfully disrupted the Roman battle formation , and then withdrew . Pyrrhus ' peltasts and archers began to fire and his phalanxes began to attack . The infantry line was near equal to the Romans ' in length . Although Pyrrhus had a small advantage in number , the phalanx was by design deeper than the legion . The phalanxes made seven attacks , but failed to pierce the legion . It had met a foe that was stronger than it had ever encountered . The Romans made seven attacks , yet it could not break the phalanx . The battle hung in the air . At one point , the battle became so pitched that Pyrrhus — realizing that if he were to fall in combat , his soldiers would lose heart and reason — switched armor with one of his bodyguards . This bodyguard was subsequently killed , and word spread through the ranks that the Pyrrhus had fallen . His force began to waver , and the Romans gave a thunderous cheer at the turn of events . Grasping the magnitude of the situation , Pyrrhus rode forward , bare - headed , along the lines of his men to show he was still living . This show of bravery strengthened their resolve , and the battle raged on . Unable to make any significant gains in action , Pyrrhus deployed his elephants , held in reserve until now . The Roman cavalry was threatening his flank too strongly . Aghast at the sight of these strange and brooding creatures which none had seen before , the horses galloped away and threw the Roman legion into rout . Pyrrhus then launched his Thessalian cavalry among the disorganized legions , which completed the Romans ' defeat . The Romans fell back across the river and Pyrrhus held the field . In the opinion of Dionysius the Romans lost 15 , 000 soldiers and had thousands taken prisoner ; Hieronymus states 7 , 000 . Dionysius totalled Pyrrhus ' losses at around 11 , 000 soldiers , 3 , 000 according to Hieronymus . In any rate this could be considered the earliest of his Pyrrhic victories against Rome . Order of battle . This is a possible order of battle for Heraclea . Epirus and Tarentum . Commander : Pyrrhus Roman Republic . Commander : Publius Valerius Laevinus Some of these were probably guarding the camp , thus not fighting the battle . Aftermath . After the battle reinforcements from south Italy joined Pyrrhus . The Greeks of Rhegium who wanted to join him were massacred by Roman soldiers under the command of Decius Vibelius , who was proclaimed as ruler of the town . Pyrrhus then began to march into Etruria . He captured many small towns in Campania , and his forces plundered Latium . His march was stopped in Anagni , two days from Rome , when he met another Roman army under Corunciatus . Pyrrhus was afraid that he did not have enough soldiers to fight , and knew Laevinus and Barbula were probably marching behind him . Instead he withdrew and the Romans did not follow him .