units similar to others ?

[QwertyMIDX]

Here is something of the EB stock explaination of Gaul:

Gaul was originally one big kingdom under the conquering king Ambicatus. Everything was fine for quite a while. The 'tribes' are more like feudal noble houses. The region was administered by Gobret and the Vergobret (magistrates and the high magistrate) who helped organize the various lesser kings into a cognizant body, and held a body not unlike a senate. The Biturges lost political steam, and the Aedui came to power; an Aedui Vergobret was in place, so their agenda was being served in Gaul. Everything was fine, until the Belgae and Germanic tribes began to invade the borders. The Belgae were turned back by the Carnutes, but the Germanic tribes had captured substantial holdings of eastern Gaul. Infighting caused the kingdom to collapse. The Aedui maintained legal authority, but technically were powerless over much of Gaul, except Aulercia, which had the Carnutes, who were religiously devoted to proper authority, their own tribes, and the Insubres, who were relatives. A few kingdoms and confederacies formed. There were, notably, the Armoricans, the Gallic-Britons (the southeast of Britain had been part of Ambicatus's kingdom), Aquitae or Aquitannae (which included the Lemovicians and their subjects), and most importantly, the Arverni 'Alliance'.

The Arverni were in an alliance with the Volcae and Sequanes, but this was more a state of subjection; they abolished the magistrative government and had a monarchy with electors and a warrior-senate. The Arverni king and body of electors, to prevent old loyalties from cropping up to the druids, abolished worship of Cernunnos, the druidic god of Gaul, and encouraged worship of Sucellos, a common Celtic god, but usually worshipped in much less extravagant a fashion in Gaul. The Arverni began raiding Aedui caravans, which was a blatant disregard for the law. They were at first little more than another subset of the numerous rebels, and ideologically were probably seen as little more than a pack of criminals. However, they were a pack of criminals with an army. The Aedui were eventually more or less subject to their will for a while, but the war kicked back up in earnest. Eventually, Gauls were choosing sides again, and Gaul began to unify, either as subjects of the Arverni, or a sub-state of the Aedui. Before the Roman invasion, they controlled all of what remained of Gaul (what wasn't under Germanic or Roman control) between them; as an aside, power shifted in the alliance, to the Sequanes, who had a string of kings.

The Germans were invading again, so the Aedui sent a magistrate to Rome to ask for assistance, as they were hemmed in by two enemies. Not all of the Aedui's senate wanted this though, and there was much argument. Eventually, those who wanted to ally with Rome were left without a government, and allied themselves to Rome. The rest fell apart in arguments about the best course of action. Rome immediately gained defacto control over much of Gaul without a fight. All there was left to do was to defeat the Sequane/Arverni alliance, who were already pretty drained from the lengthy war, and to secure the border from the Germanic tribes. After that, it was more mopping up than anything. The whole country had utterly collapsed. It hadn't been that way, that wasn't the normal mode of operation for the Gauls. During Vercingetorix's rebellion, his alliance with the Aedui was strained because the Aedui wanted to reestablish the magistrates, and he wanted to use the monarchy.

Hope that helps a bit.