By this victory, according to Tacitus, so complete and glorious, the Roman army was inspired with confidence to such a degree, that they now pronounced themselves invincible, and desired to penetrate to the extremity of the island.
The Caledonians now began to perceive the danger of their situation from the proximity of such a powerful enemy, and a sense of this danger impelled them to lay aside the feuds and jealousies which had divided and distracted their tribes, to consult together for their mutual safety and protection, and to combine their scattered strength into a united and energetic mass. The proud spirit of independence which had hitherto kept the Caledonian tribes apart, now made them coalesce in support of their liberties, which were threatened with utter annihilation. In this eventful crisis, they looked around them for a leader or chief under whom they might fight the battle of freedom, and save their country from the dangers which threatened it. A chief, named Galgacus by Tacitus, was pitched upon to act as generalissimo of the Caledonian army; and, from the praises bestowed upon him by that historian, this warrior appears to have well merited the distinction thus bestowed. Preparatory to the struggle they were about to engage in, they sent their wives and children into places of safety, and, in solemn assemblies in which public sacrifices were offered up, ratified the confederacy into which they had entered against their common enemy.
Having strengthened his army with some British auxiliaries from the south, Agricola marched through Fife in the summer of 84, making for a spot called by Tacitus _Mons Grampius_; sending at the same time his fleet round the eastern coast, to support him in his operations, and to distract the attention of the Caledonians. Various conjectures have been broached as to the exact line of Agricola’s march and the exact position of the Mons Grampius. The most plausible of these is that of General Roy,[9] who supposes that the march of Agricola was regulated by the course of the Devon; that he turned to the right from Glendevon through the opening of the Ochil hills, along the course of the rivulet which runs along Gleneagles; leaving the braes of Ogilvie on his left, and passing between Blackford and Auchterarder towards the Grampian hills, which he saw at a distance before him as he debouched from the Ochils. By an easy march he reached the moor of Ardoch, from which he descried the Caledonian army, to the number of 30,000 men, encamped on the declivity of the hill which begins to rise from the north-western border of the moor of Ardoch. Agricola took his station at the great camp which adjoins the fort of Ardoch on the northward. If the Roman camp at Ardoch does mark the spot where the disastrous engagement about to be noticed took place between these brave and determined Caledonians and the invincible Roman legions, it is highly probable that Agricola drew out his army on the neighbouring moor, having a large ditch or trench of considerable length in front, the Caledonian host under Galgacus being already disposed in battle array on the heights beyond. The Roman army is supposed to have numbered about 20,000 or 30,000, the auxiliary infantry, in number about 8,000,[10] occupying the centre, the wings consisting of 3,000 horse. The legions were stationed in the rear, at the head of the entrenchments, as a body of reserve to support the ranks, if necessary, but otherwise to remain inactive, that a victory, obtained without the effusion of Roman blood, might be of higher value. Previous to the commencement of this interesting light, according to “the fashion of historical literature at that time,” a speech is put into the mouth of each general by the historian Tacitus. “How much more valuable would it have been to us had Tacitus deigned to tell us something about the tongue in which the leader of the barbarians spoke, or even his name, and the name of the place where he fought, as the natives uttered it! Yet, for the great interests of its day, the speech of Galgacus was far removed from a mere feat of idle pedantry. It was a noble rebuke on the empire and the Roman people, who, false to the high destiny assigned to them by Virgil, of protecting the oppressed and striking down the oppressors, had become the common scourge of all mankind. The profligate ambition, the perfidy, the absorbing pride, the egotism, and the cruelty of the dominant people--how could all be so aptly set forth as in the words of a barbarian chief, ruling over the free people who were to be the next victims.”[11]