Why didn’t the Romans conquer Scotland? – a lively investigation of imperial Roman limits

Dr Garrett Ryan, “Why didn’t the Romans conquer Scotland?” (Toldinstone, 18 June 2022)

Generations of British and other schoolchildren studying Roman history must have wondered why the Romans successfully made two-thirds of the island of Britain part of their empire but failed to make Scotland, then known as Caledonia collectively, their own. In this lively mini-documentary, Dr Garrett Ryan addresses what students must have puzzled over during their lessons and homework, and perhaps even asked their teachers who themselves must have been just as perplexed that the Romans never brought the whole island of Britain under imperial rule. He brings up various plausible reasons as to why the Romans eventually decided to leave the wild and unruly Caledonians north of Hadrian’s Wall (marking the border between Roman Britannia and Caledonia) alone – and those reasons do not necessarily have any link to the Caledonians themselves or the country in which they lived.

After briefly describing Hadrian’s Wall and what it symbolised for the Romans south of it, Dr Ryan refers to two major attempts by the Romans to conquer Caledonia. Roman governor of Britannia, Gnaeus Julius Agricola campaigned in Caledonia from 79 to 84 CE, sending a fleet to the Orkney Islands and building garrisons as far north as Aberdeen. Although Agricola won major victories against the Caledonians, he was recalled to Rome in 85 CE, and with that recall the Romans gave up further attempts at conquest. More than a century later, the Emperor Septimius Severus, irked at Caledonian raids into northern Roman Britannia, invaded Caledonia with a huge army of 50,000 men in 208 CE. After much heavy and brutal fighting, with huge casualties on both sides, the Caledonians sued for peace and gave up control of the Scottish Lowlands region. Septimius Severus was a harsh ruler and resorted to genocide when one of the Caledonian tribes revolted but his illness in 210 CE and death in 211 CE put an end to further campaigning in Caledonia. Severus’s sons Caracalla and Geta, inheriting their father’s throne as co-rulers, made peace with the Caledonians and withdrew Roman troops to south of Hadrian’s Wall.

So it seems that it was a matter of luck that two Roman attempts to invade and colonise Caledonia failed – but why then, did the Romans not try a third time to conquer Caledonia? Dr Ryan considers the possibility that the mountainous landscapes of Caledonia, together with the cold and rainy climate, might have put Roman armies at a disadvantage … but then goes on to point out that Roman armies successfully conquered and colonised equally mountainous areas such as Greece, the Pyrenees between Gaul and Iberia, and the Alpine region in west-central Europe. The interior parts of Anatolia had bitterly cold winters and many other parts of the Roman empire, not just Britain, had equally damp temperate climates.

Dr Ryan goes on to observe that, financially, Roman Britannia was a drain on Rome in terms of what Rome expended on its northwest colony (in defence and infrastructure) and what Rome got out of its investment, which was not a great deal. Britain did provide minerals, notably tin and iron, but it was never one of Rome’s more prosperous provinces. Far from Rome and cold, misty and damp, with a population that was pacified only after decades of warfare and on occasions outright genocide, Roman Britannia was obviously an unappealing place for soldiers and administrators to be posted to. A Roman Caledonia would have been even more remote and colder and more rainy still, and its indigenous inhabitants just as resistant to harsh Roman rule and exploitation, with perhaps even less to offer Rome than what Roman Britannia had.

In short, why the Romans did not conquer Scotland can be explained using a cost/benefit analysis approach: for what the territory was worth, the cost of conquest and subjugating the Caledonian tribes, even exterminating them, was perhaps far too much for Rome to stomach. The physical limits of communication, given the technology available to Rome at the time, had been reached with Britain and Germania: this would help explain also why Hibernia (Ireland) was never conquered by Rome despite Rome and the Irish having many commercial and cultural contacts over several centuries.