Republican Army

[drsrob]

The basic differences between the Polybian and the Caesarian legions can be surmised as follows. (The list is not exhaustive, by the way)

Armament and equipment:

• 1. the spear (hasta) of the triarii was abolished;
  2. the mail shirt was (probably) carried by all;
  3. the triple crest was replaced by a single drooping horsehair crest.

Organization:

• 1. the manipuli were grouped into cohortes of 3 manipuli each. Of these the senior centurion had tactical control, as earlier in the manipuli;
  2. there was apparently no longer any difference between hastati, principes or triarii;
  3. the velites had disappeared, but there is mention of special infantrymen, called antesignani;
  4. The citizen cavalry had disappeared in all but name.

Service and pay:

• 1. several provinces had what seams to be a more of less permanent garrison, though in times of war legions were still raised for the duration;
  2. since the Gracchi (late 2nd century BC) the soldiers were issued clothing for free, a benefit apparently withdrawn by Caesar in return for a raise in pay.

Lack of sources make it difficult to determine just when and in what order these changes came about. For instance the cohors was already mentioned by Polybius as an extraordinary unit. Perhaps it was originally a recruiting unit of the allies. Possibly they became permanent units during or as a result of the Jugurthan War, when the army was spread over a great numer of small fortlets. For a battle of 86 BC Frontinus speaks of 1st and 2nd battle lines without reference to hastati or principes, so the change had accured before said date.
In a cohors the manipuli would be posted side by side with the senior unit in the position of honour on the right. We can assume that the abolition of the spear (hasta) was a result of this tactical change, but we don't know this. The same goes for the disappearance of the age-difference between the various manipuli. That the triarii took up position on the right can be deduced from the fact that their very name was dropped and replaced by that of pilani.
The velites were last mentioned in the same battle of 86 BC. The antesignani were first mentioned by Caesar when describing the events of 49 BC. There are good clues suggesting that the latter were a continuation of the first.

• a. Polybius (VI, 22) says that the velites wore no armour and a simple helmet covered with a wolfskin or something similar. Vegetius (ERM 2.16) says that the antesignani wore lighter armour and a bearskin over their helmets.
  b. Three quotes:
  • M. Terentii Varronis Saturae Menippeae 22. 552, 25 et 555, 8:
    quem secuntur cum rotundis velites leves parmis, antesignani quadratis multisignibus tecti
    ...because the light velites were cut to pieces(? while equipped) with round parmae, the antesignani (well) protected by multifigured square ones...
    Festus, 238:
    Parmulis pugnare milites soliti sunt. Quarum usum sustulit C. Marius, datis in vicem earum Bruttianis
    'Soldiers used to fight with small bucklers. The use of which C. Marius has abolished, with Bruttians given in their place'
    Festus, 26:
    Bruttianae parmae dicebantur scuta quibus Bruttiani sunt usi.
    'Bruttian bucklers were the shields called that the Bruttians used to use.'

Taken togeter these quotes show that Marius (and others?) gave the velites better protection and strongly suggest that they evolved into antesignani.
According to J.B. McCall the Citizen cavalry ceased to be called out from the Social War (90 BC) onwards. The only certainties are however, that it still existed in 102 BC and probably in the 90ies and that Caesar had none in 58.