Realisitc use of auxiliaries

[KhaziOfKalabara]

1. Whenever I raise auxiliary units, I try not to use them against the culture they hail from, so, for example, I avoid using Boii Gauls against the Aedui/Arverni, or Numidians against other Numidians (mercenaries are a different matter). I do it on the assumption that this way they're less likely to join their brethren and turn against me (as if that could happen in RTW), but I guess that's not really realistic, is it now?

Should I just forget all about it and use Gauls vs Gauls, Numidians vs Numidians, Germans vs Germans etc.as I see fit?

I would actually almost encourage the opposite, i.e., mainly use regional troops against others of the same culture. If you think about the speed of communications at the time and the distances involved, the majority of rivalries would be local, and in a largely monarchical / oligarchical society there would also be pretenders, the disenfranchised or sidelined heirs for an greater power to use as an excuse for intervening.

Some factions might be expected to be naturally fissiparous (oh, I love that word), for instance Rome (think of the Social War, and revolts of the Italian allies during the Punic wars) and the Seleucids (breaking up into various mini-kingdoms and a rump state). Others, including most of the barbarians plus the KH, represent federations where political tensions may also come to the fore. And a further set (e.g., Pahlava, Ptolemaioi, Carthage in Spain, Epirus and Rome in the mid-later game) represent a ruling class imposing themselves on subject people of a different cultures - depending on the regions where the conflicts happen - and those subject peoples might be more than happy to support an invader on the assumption they might achieve more autonomy under new rulers.

So all in I'd positively recommend throwing auxiliaries of any stripe against troops of their own culture, as an abstraction of all the above.

[Centurion Crastinus]

Since the Romans used auxilary troops during the era after the Marian Reforms, why are their not Eastern and Western Auxilia after the Marian Reforms? I know that any levy infantry can be used after the Marian Reforms, so why not keep it the same during the Imperial era? I do prefer the imperial auxillia though.

[Watchman]

AFAIK those represent specifically the post-Augustinian reorganisation of the Auxilia into similar standardised patterns as the Legions proper; until then the auxiliaries had pretty much just been fighting in their "native" fashion aside Roman troops, although in some cases at least the Romans had made a point of supplying and requiring better armour (to give their mates an edge over the natives, usually) - see for example the regional cavalry auxilia types.

[Centurion Crastinus]

Thanks Watchman.