By 80 AD the Roman governor, Agricola, felt secure enough in the south of Britain to begin an invasion of the north, building a string of forts across the Clyde?Forth line and defeating a large force of Scottish tribes at Mons Graupius. The long-term effect of his campaign, however, was slight. Work on a major fort - to be the base for 5000 soldiers - at Inchtuthill, on the Tay, was abandoned before it was finished, and the legions withdrew south. In 123 AD the emperor Hadrian decided to seal the frontier against the northern tribes and built Hadrian?s Wall, which stretched from the Solway Firth to the Tyne and was the first formal division of the island of Britain. Twenty years later, the Romans again ventured north and built the Antonine Wall between the Clyde and the Forth. This was manned for about 40 years, but thereafter the Romans, frustrated by the inhospitable terrain of the Highlands, largely gave up their attempt to subjugate the north, and instead adopted a policy of containment.

It was the Romans who produced the first written accounts of the peoples of Scotland. In the second century AD, the Greco-Egyptian geographer Ptolemy drew up the first-known map of Scotland, which identified seventeen tribal territories. Other descriptions were less scientific, compounding the mixture of fear and contempt with which the Romans regarded their Pictish neighbours. Dio Cassius, a Roman commentator writing in 197 AD, informed his readers:

'They live in huts, go naked and unshod. They mostly have a democratic government, and are much addicted to robbery. They can bear hunger and cold and all manner of hardship; they will retire into their marshes and hold out for days with only their heads above water, and in the forest they will subsist on barks and roots.'