THE dawn of Scottish history began with a battle on an Aberdeenshire hill in 84AD. On one side of the field were the vast legions of the mighty Roman Empire. On the other, a 30,000-strong confederate army of Caledonians – our Scottish ancestors. This encounter, which became known as Mons Graupius, was a key moment for the Romans in their almighty struggle to conquer the whole of Britain. For the Scots, it was a battle for survival against a brutal occupation.

“Robbery, butchery, rape: the liars call it Empire,” roared Calgacus, leader of the Caledonians, at the men gathered before him. “They create a desolation and call it peace. Whether you are to endure slavery forever or take summary vengeance, this field must decide.”

In the event, Calgacus and his brave warriors marched into a defeat at the hands of General Agricola, the Roman leader. The legions forced their adversaries to melt away into the great forest . But the Caledonians’ fate would not be decided that day, as Calgacus had believed. Although the Romans won at Mons Graupius, they would never win the war against Scotland.

We should, nonetheless, be grateful that Rome decided to invade this remote corner of Europe. Had the Empire failed to penetrate so far north following the initial conquest of south Britain in around 43AD, we would know next to nothing about the natives. Calgacus – whose name means “swordsman” – is, after all, the first Scot in recorded history.

His identity, and virtually all that we know about our early forebears, was recorded for us by Tacitus – historian of the Roman campaign in Britain (and Agricola’s son-in-law). What Tacitus tells us should not be taken at face value. He aimed to write a glowing biography of Agricola and use his talents as a rhetorician to criticise Rome. He put noble words in Calgacus’s mouth to contrast the freedom-loving, uncorrupted Caledonians with the slavery of the south Britons, tainted by the vice, greed and arrogance of an autocratic empire, which Tacitus considered to have fallen after the golden age of the republic.

Mons Graupius should have been the beginning of a long haul to conquer the Caledonians. But instead, Agricola marched south to winter quarters. With reinforcements required on the Rhine and Danube, the Romans were obliged to give up on Scotland and withdraw to bases in safer southern territory.

In 122AD, just over two decades after Mons Graupius, the building of Hadrian’s Wall began between the Tyne and the Solway. Another 20 years later, a replacement wall of turf was erected between the Forth and Clyde on the orders of Emperor Antoninus Pius – who demanded the reoccupation of much that had been gained and then lost. But the Antonine wall, too, was abandoned under Emperor Marcus Aurelius around 163AD.

Only a handful of outposts would remain beyond the recommissioned Hadrian’s Wall and, by 215, the northern forts were abandoned. From then on, “the hill people of the north and west,” as they came to be known, would be a constant threat.

But Rome’s footprints would never be erased from the minds of Caledonians and the painted northern tribes known as the Picts . Square Roman encampments – with their distinctive straight sides with rounded corners, like enormous drinks coasters – can still be seen as crop marks in some areas .

The remnants of the mightiest marching-camp in the northeast – with space for 30,000 men – can be found at Logie Durno, adjacent to Bennachie hill, near the field where Mons Graupius was probably fought. Enduring as their ghostly outlines are, however, these were not permanent garrisons and attempts to build such had to be aborted.

But besides military engagements, what of the human contact Romans had with the tribes of early Scotland? “We’ve always had to rely on cloak-and-dagger men operating beyond Hadrian’s Wall,” wrote one frontier commander, “but we will need more than spies to win the hearts and minds of the frontier people”. For the most part, the Picts seem to have been almost as mysterious to Roman writers as they are to us.

We don’t even know what name the Picts had for themselves. Did these mountain guerrillas run into battle with their naked bodies covered in elaborate tattoos, as some classical writers suggest? What is the significance of the Picts’ enigmatic standing stones, ornately carved with bulls, birds and fish, as well as other curious symbols? Why the abstract depictions of everyday objects like combs and mirrors? We don’t really know. A debate currently rages over what kind of language the Picts spoke, and which gods they worshipped. There is even an argument that the early Scottish Gaels and the Picts, all adept sailors, were broadly one and the same people. The identity of the tribes who resisted Rome has been a political hot potato for centuries. Was Britain conquered in whole or only in part? England has often argued that Rome’s dominion was complete, while the Scots, perhaps predictably, have disagreed.

The mediaeval manufacture of a united British history with Roman origins can be found in the ninth-century chronicles of Nennius. “The island of Britain is so called from one Brutus, a Roman consul,” he wrote, “and it lives in four nations, the Irish, the Picts, the Saxons and the Welsh.”

This history was remoulded to make a virtue of the Roman conquest of southern Britain by 12th century Welsh chronicler Geoffrey of Monmouth. He invented a new Brutus, the founder of Britain and great-grandson of Aeneas of Troy, who in turn had founded the Roman republic.

This Brutus myth was used in the 13th century by England’s Edward I to justify his claim to Scotland. He argued that Brutus had been emperor of all Britain, and had given England and lordship of Britain to his eldest son Locrinus, while he left Scotland and Wales to his younger sons, Albanactus and Camber. After they died, Locrinus claimed the lot. The Scots rejected this as imperialist claptrap, but were equally keen to invent their own classical beginnings – the badge of any self-respecting mediaeval nation. The classical origin myth of an independent Scotland contained in the Latin text of the Declaration of Arbroath carries more than a hint of the rhetoric of Tacitus when arriving at the country’s then predicament. “It is in truth not for glory, nor riches, nor honours that we are fighting, but for freedom – for that alone, which no honest man gives up but with life itself.”

Even after the Union with England in 1707, the Scots remained ambivalent about the extent of Agricola’s success. The philosopher David Hume wrote that he had “only pierced the forests and mountains of Caledonia”, before cutting off the “ruder and more barren parts of the island”.

There were others during the 18th century who celebrated the Caledonians as an early sign of Scotland’s capacity to endure under the weight of the new Rome: the British Empire. But the question everyone needed answering was: were the Caledonians a race of Gaels or Goths?

This was a matter of profound importance in a nation seeking new ways to define itself. On the one side were those who argued that the Caledonians were Gaelic-speaking Highlanders. On the other, those who claimed they had been Scots-speaking Lowland Goths from northern Europe. Indeed, Tacitus had conjectured that “the ruddy hair and large limbs of the Caledonians point out a German derivation”.

The early Gothic connection even gave rise to speculation about the origins of the kilt. Of the Germans, Tacitus had once said: “They all wrap themselves in a cloak which is fastened with a clasp – leaving the rest of their persons bare.”

But then, perhaps the Caledonians got the idea for the kilt from seeing the Roman toga. It was Tacitus himself who remarked of the early British Celts that: “A liking sprang up for our style of dress and the ‘toga’ became fashionable.”

This observation encouraged many 19th-century antiquarians to comment on the striking similarity between the dress of the kilted Scottish regiments and that of the ancient Roman legions. Could it be that besides the crop-circles and ridges that indicate long-vanished forts and highways – or the ruined altars, ornate battle masks and jewellery dug up by archaeologists – the greatest legacy the Romans bequeathed to Scotland was actually our national dress?