The army of the late republic
The legions
The auxilia

The Roman army of the late republic is often connected to the socalled Marian army reforms. In fact radical reforms of the army structure were few. What novel measures were taken, were moreover in fact the work of other generals than Gaius Marius. One of the more current misconceptions regarding the Roman army in the later republican era concerns the introduction of a professional army recruited from volunteers to replace the militia army composed of conscripts. Conscription was not ended by the fact that Marius accepted volunteers from the capite censi. Draftees rather than volunteers continued to provide the bulk of legionary recruits. Neither is there much actual evidence for wide ranging organisational and tactical reforms by the great general. The cohors appears to have been incorporated in the regular organisation well before the days of Marius. Although gladiatorial trainers were employed as an emergency measure by Rutilius Rufus after the defeats inflicted on the Romans by the Cimbri and Teutones there are no indications available that this entailed a drastic improvement in training standards. It is also very doubtful that instructors of this unsuitable background continued to be employed after the emergency situation had passed. The light infantry velites were not abolished by Marius, merely being equipped with different shields and continuing to serve in the wars of Sulla against Mithridates. One measure however is very closely associated with Marius. This general reduced the size of the legion's baggage train by requiring his soldiers to carry much of their equipment themselves. This resulted in the heavily laden legionaries being nicknamed muli Mariani or Marius's mules.

The command structure of the Roman army underwent considerable changes in the late republic. The role of the consules as the primary commanders of Rome's legions diminished, finally being ended by the Sullan reforms of the constitution. In their stead proconsuls and commanders granted extraordinary powers were now the most important army leaders. The restriction on the maximum number of legions under the command of a single general was lifted. Armies could now be made up of up to several dozens of legions. The nature of the army also changed with soldiers being loyal to their commanders rather than the Roman state itself. The fact that campaigns in this period tended to be more prolonged and the securing of discharge benefits by the personal influence of the generals attached the soldiers much more closely to their leaders.

Legionary recruitment
Legionary organisation
Legionary officers

The legiones provided the citizen troops of the Roman army. As a result of the expansion of the empire the number of units under arms at any given moment had risen since the middle republic. Some of these units remained in service for longer periods, discharging soldiers who had served their time and accepting new recruits in their place. These semi-permanent units began gradually to develop their own distinctive identity, a process accelerated by the prolonged Gallic campaigns of Caesar and the civil wars that followed it. With different parties in the civil wars each levying their own armies, legionary numerals started to be duplicated. Legions started to adopt honorary cognomina and acquire particular symbols and signs. Some commanders valued this esprit de corps of their legiones to such an extent that they preferred to levy new units rather than dilute their veteran formations with the influx of new men.

Legionary recruitment

Contrary to popular opinion the majority of legionary soldiers in this period remained levied conscripts rather than volunteers drawn from the capite censi. The property qualifications that had already been lowered several times in the previous decades however appear to have been waived altogether. To enlarge the legionary strength legiones vernaculae were raised from provincials rather than Roman citizens on several occasions, notably during the civil wars of the first century BC.

Men enlisted in the army now generally had to serve for longer periods of time and were often from an impoverished agrarian background. Roman generals interested in gaining the loyalty of the troops were therefore keen on securing special discharge benefits for their men. This often took the form of distribution of land to time served soldiers. For this purpose land was on several occasions confiscated on a huge scale, both in Italy as well as the provinces.

Service conditions were greatly improved during the civil wars. Previously pay had barely covered expenses and soldiers gained only by the opportunities for plunder. The fighting between the various civil war parties enabled the loyalty of the troops to be converted in wealth. Commanders anxious to attach the legionaries to their cause distributed generous bounties known as donativa to their troops on a regular basis. Caesar did much to enlarge his popularity by doubling the standard rate of pay and providing silvered and gilded equipment to his men. The provision of weaponry and equipment by the Roman government and commanders to the troops remained an exception to the rule, the soldiers still being expected to equip themselves at their own expense.

Legionary organisation

The composition of the legio in the late republic was different from the earlier formations. The light infantry velites disappear from the records after the battles of Sulla in Asia Minor, their role being taken over by a mix of legionary antesignani and auxiliary skirmishers. The units of the triarii were by now brought up to the same strength as those of the hastati and principes and by this date carried the pilum in place of the thrusting spear. Ten cohortes combining manipuli of hastati, principes and pili with the same number had become part of the regular legionary organisation. The battle formation of the legion also changed. The triple battle lines of ten manipuli had either been replaced or supplemented by a new formation with four cohortes in the first and three cohortes each in the other two battle lines. This new deployment meant that the legion now had twelve rather than ten manipuli available for action in the front line.

The old legionary cavalry recruited from the equites Romani disappeared from the legionary organisation at some point in the first century BC. This may have left the legio without an integral cavalry arm. However if speculatores in this period were mounted troops as their imperial counterparts certainly were, a very small number of legionaries may have been cavalrymen. The apparent lack of substantial citizen cavalry was made good by recruiting large numbers of barbarian and provincial horsemen. The Bellum Gallicum relates of one interesting occasion when Caesar had the entire legio X mounted on horses from the auxiliary troopers to serve as a reliable cavalry guard during a meeting with the German chieftain Ariovistus.

In the civil wars commanders spent much effort in the formation of loyal elite units. This was partly achieved by employing foreign bodyguards from barbarians with a high reputation for loyalty and devotion to duty. Hispanic, Gallic and German horsemen served widely as personal guards. However picked citizen troops also played an important role. Caesar established the legio X Equestris as his favourite unit while other commanders selected legionary soldiers for service in cohortes praetoriae or bodies of speculatores. The antesignani were another elite corps picked from the bravest legionaries and employed in a variety of roles including light infantry skirmishing as well as spearheading assaults.

Legionary officers

There were some changes in the structure of the legionary officer corps compared to the legions of the middle republic. The status and remuneration of the centuriones in the Roman army was significantly raised in the late republican period. This was in recognition of their importance to the army. The pay raise for the centurions may well have been accompanied by an increase in pay to the non commissioned officers which would eventually emerge as the principales of the imperial army. Legionary tribuni which had previously included men of great experience, were by this date often young and lacking in experience. This resulted in the command of legiones being given to legati appointed by the army commander rather than to the senior tribunus. These legati had however not yet developed in the similarly named legionary commanders of the imperial army as they were not attached to particular units and regularly shifted commands.

After the Social War waged against the Italic allies Roman citizenship was granted to all of these below the river Po. This meant that Italic soldiers were now directly recruited in the legiones rather than serving in separate alae sociorum. Auxiliary forces from outside Italy were however employed on a large scale. Many of these forces were raised for specific campaigns and disbanded as soon as their services were no longer needed. Only a minority of these units, notably cavalry, achieved a semi-permanent status.

Part of the auxiliary forces levied for service in the Roman army were organised on the Roman pattern in cohortes and alae of some 500 men. Command of these units was partially entrusted to nobles from the communities that supplied the troops, though legionary centuriones and equestrian officers were also employed. Equipment and tactics of the auxiliaries were for a large part those of their native regions. Some units however were equipped and trained according to Roman standards. A peculiar feature was the formation of some cavalry formations as more or less private armies of retainers by Roman officers, the ala Scaevae being an example.

Little is known of the remuneration and other service conditions of the auxiliary forces. During earlier times allies received upkeep from the Roman state but no regular pay was provided. Other troops though are described as mercenaries in the sources indicating that at least some auxilia were paid for their services. To a limited extent auxiliary soldiers with good service records were granted Roman citizenship. However these grants were made to individuals and were not a regular occurence. Only after the reign of the emperor Claudius would time served soldiers in the auxilia receive citizenship on a regular basis.