Successive prætors had failed to establish tranquillity in Britain, or to obtain the submission of the people, when Agricola, father-in-law of the celebrated historian Tacitus, arrived in his turn in this indomitable island. His brilliant exploits soon caused him to be respected; but, while pursuing year by year the course of his conquests, he endeavored to found the Roman rule upon the most durable basis. In his hands the civil administration became milder; the Britons governed with justice, became gradually less estranged from their conquerors. {19} A taste for luxury and Roman civilization began to distinguish the chiefs admitted to the prætorian court; the Roman toga took the place of the British mantle; buildings arose upon the model of the Roman constructions; children began to speak Latin; and at the same time the spirit of liberty and resistance diminished among the inhabitants of the south of Britain. "The Britons willingly furnish recruits to our armies," wrote Tacitus; "they pay the taxes without murmuring, and they perform with zeal their duties towards the government, provided they have not to complain of oppression. When they are offended their resentment is prompt and violent; they may be conquered, but not tamed; they may be led to obedience, but not to servitude." The military progress of the Roman general was no less important than his moral conquests. He had reached the Firth of Forth and the narrow isthmus which separates this river from the mouth of the Clyde. After every new victory he protected the subjected territory with forts. He even constructed a wall, the ruins of which, crossing the north of England from the Solway to the mouth of the Tyne, bear to this day his name. In the eighth and ninth year of his government he passed the line of the forts and penetrated into Scotland, the country of the Caledonians, savage tribes who had not yet beheld the Roman eagles. Scarcely had the conquerors invaded this new territory when the Caledonians, under the command of their chief, Galgacus, descended from the Grampian hills and fell upon the invader. On Ardoch Moor traces of the combat still exist, together with the lines of the Roman encampment. The struggle lasted all day, and the barbarians were defeated; but on the morrow at sunrise they had disappeared, and the Romans found themselves alone in the midst of a wild country. {20} In their flight the Caledonians had set fire to their habitations, and with their own hands had slain their wives and children, to prevent their falling victims to the vengeance of the conqueror. The savage tribes had returned into their mountains, leaving, according to the chronicles, 10,000 dead upon the field of battle. Agricola made no effort to pursue them. Falling back towards the south, he despatched his vessels to make a voyage of exploration all round the island, the northern shores of which had not yet been visited. The mariners returned,