Much recent work on the auxiliary units of the Roman army has concentrated on the cavalry, including their role and effectiveness in battle. Experimental archaeology has additionally illustrated how effective the cavalry could be with the Celtic style saddle, in spite of the lack of stirrups. As a result, the Roman cavalry is now seen by some modern commentators as something of an elite wing of the army. The auxiliary infantryman, on the other hand, is generally regarded as nothing better than foreign expendable ‘cannon-fodder’. This view, it seems, has its origin partly in Tacitus' famous commentary on the tactics of his father-in-law Agricola at Mons Graupius. There is, in fact, little other evidence to support this view, and Agricola probably had other reasons for his dispositions at the battle which his biographer does not mention. Rather than merely a piece of ‘cannon-fodder’, the auxiliary infantryman of the Principate should instead be seen as a competent fighting soldier who fulfilled an invaluable role in the Roman army.