If the Marian reforms’ effects on Roman society were monumental, their effects on the Roman military were downright colossal. Completely abandoned was the Manipular Legion with its three lines of distinct styles of infantry. In its place was the glossy new Cohortal Legion, consisting of Romans old and young, affluent and landless, all standing side by side beneath the glorious banner of SPQR. The new Legions were simpler, easier to organize, and packed a much heavier punch, equipped as the new legionnaires were with state-supplied arms and armor.

Legionnaire

The legionnaire continued to fight his battles with gladius and cylindrical scutum. The pilum had evolved by the time of the Marian reforms; the iron head was now attached to the shaft via wooden pegs that would break upon impact, rendering the pilum unsalvageable to its target. Much later in Roman Imperial history, during the reign of Tiberius in the very early first century AD, legionnaires adopted the iconic lorica segmentata. This new armor made a Roman army exponentially cheaper and quicker to equip without sacrificing the protection of chain mail.

Centurion

Centurions fought with the same weapons as the legionnaires they led. However, centurions bore two pieces of equipment that made them easily identifiable both on and off the battlefield. The helmet of a centurion was transversely crested, making the officer easy to spot in the chaos of the melee. Centurions also carried a vitis, a small stick, around camp to deal physical punishment to insubordinate miles, the vanguard legionnaires. Also of note is the fact that centurions’ swords hung from the left side of the hip, as opposed to the usual hanging from the right side of the hip.

Auxilia

Out the door were the velites and equites of the Manipular Legions; all non-legionary troops were now organized under the broad title of auxilia. Light skirmishing infantry still appeared on the battlefield, but as the Roman Empire expanded, entire ethnicities were now kept together and fought together, such as Balaeric slingers and Cretan archers. In a move likely aimed at a then-hostile aristocracy, Gaius Marius abolished the equestrian class of soldier altogether. Roman cavalry was still organized by turmae, but was now state-trained and equipped and typically recruited out of local tribes. Julius Caesar especially used the new equites auxilia to great effect, supporting his Roman legionnaires with recently conquered Gallic horsemen as he advanced into Gaul in the first century BC.