The Romans, who had already made themselves masters of South Britain, were led into the northern part of the island by Julius Agricola, a.d. 80. But the Celts whom they found there, and whom they called Caledonians, were so well able to defend themselves among their mountains that the Romans, though they defeated them in a great battle on the Highland border, gave up the idea of conquering the country, and retreated again south of the Firths of Forth and Clyde...