After the defeat by the Cimbri, during the Marian Reforms, three of the four animal standards were discarded (Minotaur, wolf and boar) and only the Aquila left.
This seems like an oddly superficial change for reforms which otherwise seem very practical. Was this a case of unity to one symbol or is there a definitive purpose?
Anybody able to clarify this point for me? Thanks!
This is what Pliny the Elder wrote:
Caius Marius, in his second consulship, assigned the eagle exclusively to the Roman legions. Before that period it had only held the first rank, there being four others as well, the wolf, the minotaur, the horse, and the wild boar, each of which preceded a single division. Some few years before his time it had begun to be the custom to carry the eagle only into battle, the other standards being left behind in camp; Marius, however, abolished the rest of them entirely. Since then, it has been remarked that hardly ever has a Roman legion encamped for the winter, without a pair of eagles making their appearance at the spot.
Marius' second consulship was in 104 BC, his first year commanding a consular army stationed in Further Gaul poised to stop the Cimbri from crossing the Alps. Frontinus said he took command of the army raised the year prior by P. Rutlius Rufus, as it was well disciplined and trained (to also include advanced training techniques on sword fighting taught to the rank and file by gladiator trainers that would end up being adopted by many after Rufus, including Marius, Sulla, Pompey, Caesar, etc). So any reforms done during the Cimbri War by Marius only affected that army, specifically its two Roman legions and two Socii ala, including any citizen cavalry and definitely socii cavalry. This is important, as one must realize that a legion at this time only encompassed the Romans, and included all fighting troops types, light and heavy infantry, and cavalry.
My analysis is thus, originally each legion had in previous times carried numerous standards into battle. At the lower levels these included the standards of their infantry maniple or turma (cavalry troop). At the legion level there were five, the Eagle the chief of the legion, known to be carried by the Primus Pilus Century, while the other four were likely carried by the primus maniples or turma of the hastati, principes, triari (not counting primipilus), plus the citizen cavalry.
However, there is no tactical reason to need them all. Each subunit carried their own maniple or turma standards, so there really isn't a point taking more individuals away from combat roles to guard standards that don't matter. Leaving them back in camp gains each unit another sword or spear, less confusion as to what troops need to be looking for (their own standard and the eagle).
Plus, for a penny pincher trying to save money (a chief reason for many of the late Republic reforms) scrapping the extra standards means saving money as senior standard bearers made more salary (at least by the 1st AD).
It likely wasn't that big of a deal either, since Pliny said that for some time the others weren't used anyway, so Marius just finally made custom into an official order for his army, and then others copied him afterwards.
Strange enough, this custom wasn't 100% because Caesar is noted to have used a boar standard, as had other legions afterwards.