The cavalry consisted of German and Noric mercenaries, whose usefulness and trustworthiness had been proved in the war against Vercingetorix.
The eight years' warfare, full of varied vicissitudes, against the Celtic nation--which was brave, although in a military point of view decidedly inferior to the Italian--had given Caesar the opportunity of organizing his army as he alone knew how to organize it.

The whole efficiency of the soldier presupposes physical vigour; in Caesar's levies more regard was had to the strength and activity of the recruits than to their means or their morals.

But the serviceableness of an army, like that of any other machine, depends above all on the ease and quickness of its movements; the soldiers of Caesar attained a perfection rarely reached and probably never surpassed in their readiness for immediate departure at any time, and in the rapidity of their marching.

Courage, of course, was valued above everything; Caesar practised with unrivalled mastery the art of stimulating martial emulation and the esprit de corps, so that the pre-eminence accorded to particular soldiers and divisions appeared even to those who were postponed as the necessary hierarchy of valour.
He weaned his men from fear by not unfrequently--where it could be done without serious danger--keeping his soldiers in ignorance of an approaching conflict, and allowing them to encounter the enemy unexpectedly.

But obedience was on a parity with valour.
The soldier was required to do what he was bidden, without asking the reason or the object; many an aimless fatigue was imposed on him solely as a training in the difficult art of blind obedience.
The discipline was strict but not harassing; it was exercised with unrelenting vigour when the soldier was in presence of the enemy; at other times, especially after victory, the reins were relaxed, and if an otherwise efficient soldier was then pleased to indulge in perfumery or to deck himself with elegant arms and the like, or even if he allowed himself to be guilty of outrages or irregularities of a very questionable kind, provided only his military duties were not immediately affected, the foolery and the crime were allowed to pass, and the general lent a deaf ear to the complaints of the provincials on such points.