Hastati Hastati ( singular : " Hastatus " ) were a class of infantry in the armies of the early Roman Republic who originally fought as spear men , and later as swordsmen . These soldiers were the staple unit after Rome threw off the Etruscan rule . They were originally some of the poorest men in the legion , and could afford only modest equipment — light chainmail and miscellaneous equipment . The Senate supplied their soldiers with only a short stabbing sword , the gladius and their distinctive squared shields . The Hastati soldier was typically equipped with these , and several soft iron tipped throwing spears called pilla . This doubled their effectiveness , not only as a strong leading edge to his cohort , he was also able to pelt the enemy as a stand alone missile troop . Later , the " hastati " contained the younger men rather than just the poorer , though most men of their age were relatively poor . Their usual position was the first battle line . They fought in a quincunx formation , supported by light troops . The enemy was allowed to penetrate the first battle line consisting of hastati , which then the enemy would deal with the more hardened , seasoned soldiers , the principes . They were eventually done away with after the Marian reforms of 107 BC . History and deployment . " Hastati " appear to have been remnants of the old third class of the army under the Etruscan kings when it was reformed by Marcus Furius Camillus . The third class stood in some of the last few ranks of a very large phalanx were equipped in a similar manner to " hastati " , but more often than not were relegated to providing missile support to the higher classes rather than fighting themselves . It is probable that engagements with the Samnites and a crushing defeat at the hands of the Gallic warlord Brennus , who both used lots of smaller military units rather than a few very large ones , taught the Romans the importance of flexibility and the inadequacy of the phalanx on the rough , hilly ground of central Italy . Camillan system . By the 4th century BC the military the Romans had inherited from the Etruscans was still in use . Though its efficiency was doubtful , it proved effective against Rome ' s largely local adversaries . When Gauls invaded Etruria in 390 BC , the inhabitants requested help from Rome . The small contingent Rome sent to repel the Gallic invaders provoked a full scale attack on Rome . The entire Roman army was destroyed at the Battle of the Allia in a crushing defeat that prompted reforms by Marcus Furius Camillus . Under the new system , men were sorted into classes based on wealth ; the " hastati " were the third poorest , with the " rorarii " being slightly poorer and the " principes " slightly wealthier . " Hastati " were armed with short spears , or " hastae " , up to 1 . 8 metres ( 6 ft ) long , from which the soldiers acquired their name . They fought in quincunx formation , usually carrying " scuta " , large rectangular shields , and bronze helmet s , often with a number of feathers fixed onto the top to increase stature . They wore light armour , the most common form being small breastplate s , called " heart protectors " . In this type of legion , the 900 " hastati " formed 15 maniple s , military units of 60 men each . Attached to each maniple were about 20 " leves " , javelin - armed light infantry . The " hastati " stood in the first battle line , in front of the " principes " of the second line and the " triarii " of the third . In a pitched battle , the " leves " would form up at the front of the legion and harass the enemy with javelin fire to cover the advance of the " hastati " . If the " hastati " failed to break the enemy during their engagement , they would fall back and let the heavier " principes " take over . If the " principes " could not break them , they would retire behind the " triarii " spearmen , who would then engage the enemy in turn . The " equites " , cavalrymen , were used as flankers and to pursue routing enemies . The " rorarii " and " accensi " in the final battle line were some of the least dependable troops , and were used in a support role , providing mass and reinforcing wavering areas of the line . Polybian system . By the time of the Punic wars of the 3rd century BC , the Camillan system of organisation was found to be inefficient . In a new Polybian system , infantry were sorted into classes according to age and experience rather than wealth , the " hastati " being the youngest and least experienced . Their equipment and role was very similar to the previous system , except they now carried swords , or " gladii " , instead of spears . Each " hastatus " also carried two " pila " , heavy javelins that , " contrary to deeply entrenched myth " ( Goldsworthy ) , did " not " bend on impact to make any struck shield useless or prevent the weapon from being thrown back . The weight and barb alone sufficiently hampered any struck shield ( often penetrating the shield to hit the man behind it ) , and the iron was sufficiently hard that pila were often used as hand - held spears against both infantry and cavalry . By the time the volley of pila had reached the enemy line ( usually only fifteen yards distant for best effect ) , the legionaries were charging and very quickly at work with their swords . There was rarely any time for the foe to find a pilum , pull it out of whatever it had hit and throw it back . The " hastati " had been increased in number to 1 , 200 per legion , and formed 10 maniples of 120 men each . The " rorarii " and " accensi " had been done away with . " Leves " had been replaced with " velites " , who had a similar role but were now also attached to " principes " and " triarii " . Pitched battles were conducted in a similar fashion ; the " velites " would gather at the front and fling javelins to cover the advance of the " hastati " . If the " hastati " failed to break the enemy , they would fall back on the " principes " , who had also been re - armed with swords . If the " principes " could not break them , they would retire behind the " triarii " , who would then engage the enemy . This order of battle was almost always followed , the battle of the Great Plains and the battle of Zama being among the few notable exceptions . At the Great Plains , Scipio , the Roman general , formed his men up in the usual manner , but once the " hastati " had begun to engage the enemy , he used his " principes " and " triarii " as a flanking force , routing the opposing Carthaginian troops . At Zama , Scipio arranged his men into columns , side by side , with large lanes in between . The opposing Carthaginian elephants were drawn into these lanes where many were killed by " velites " without inflicting many casualties on the Romans . Once the surviving elephants had been routed , he formed his men into a long line with his " triarii " and " principes " in the centre and " hastati " on the flanks , ready to engage the Carthaginian infantry . Marian reforms . With the formal military reforms of Gaius Marius in 107 BC , intended to combat a shortage of manpower from wars against Jugurtha in Africa and Germanic tribes to the north , the different classes of units were done away with entirely . The wealth and age requirements were scrapped . Soldiers would join as a career , rather than as service to the city , and would all be equipped as medium infantry with the same state - purchased equipment . Auxiliaries , local irregular troops , would fulfill other roles , serving as archers , skirmishers and cavalry .