In the warming summer days, 1,900 years ago (in AD 122), the area between the Solway coast and the mouth of the Tyne was a bustling hive of activity.

A little earlier, a vast crowd had concentrated at the garrison town of Eboracum (modern York). Thousands of soldiers, imperial civil servants, and court functionaries had swamped the area. And accompanying them – as with every huge army on the move – was an alternative 'army' of sutlers, traders, conmen, pimps, and hucksters, supplying food, booze, women, souvenirs, and all (no doubt) at inflated prices.

The key person at the centre of all this frenetic activity was the Spanish-born, Caesar Traianus Hadrianus Augustus, ruler of the vast Roman Empire (from 117 to 138). He spent over half of his rule outside Italy, applying his restless energy to stabilising the frontiers of the empire and putting down armed threats to Roman rule. First, he suppressed the Jewish revolt that had broken out under his predecessor Trajan; then he put down unrest on the Danube frontier; in 122 he turned his attention to Britannia.

Roman sources suggest that there had been trouble in the northern parts of the Roman-ruled territory between 119 and 121, almost certainly from tribal groups further north (in what we now call Scotland). Now the emperor had arrived, and monumental activity was on the imperial agenda.

Long before Donald Trump became synonymous with a border-wall, Hadrian was in the imperial construction business.

Hadrian in Britain – that famous wall

The emperor's answer to the troubled northern frontier of Roman Britain was the ultimate in 'hard borders,' the wall that still bears his name. What eventually emerged (and the blueprint changed in several important ways once construction had started) was a dramatic and multi-cultural military zone, which consisted of the famous curtainwall, mile-castles, forts, barracks and civilian support settlements. It was almost 80 miles in length and stretched from the North Sea to the Irish Sea.

Once constructed, the wall was a statement of imperial power to troublesome tribal groupings further north. Such an imperial project was construction with attitude! Its entry and exit points also providing opportunities to tax and control the movement of peoples and goods, whose traditional lands had been arbitrarily divided by Roman surveyors. Plus, it kept thousands of soldiers busy and stopped boredom turning to mischief. Building a wall can have many functions.

One can imagine the form-filling, bullying, goods-inspecting, grumbling over revenues demanded, back-handers paid, as clipboard-carrying NCOs and other ranks quizzed, bullied, and extorted the passing traffic. No empire is ever constructed for the good of those conquered and certainly not for those at the bottom of the social food-chain.

But Hadrian had long gone by then. He was the initiator of the project, not its overseer. Before he left, a shrine was erected in York to 'Britannia,' as the divine personification of Britain. Coins were struck, bearing her image too, inscribed with the personalised name of the place: 'Britannia.' Hadrian had made his mark. The imperial circus packed up and moved away. By the next year (123) he was campaigning in Mauretania (North Africa), before rapidly moving away to the east, where he was on the Euphrates before the end of the year negotiating a settlement with the ever-threatening Parthians. A Roman emperor's work was never finished.

Before the end of his life, he had also initiated a series of border fortifications along the Danube and Rhine frontiers. Unlike in Britain, these mostly consisted of wooden fortifications, forts, outposts, and watchtowers. Hadrian initiated a policy of consolidation and stabilisation, as he tackled the demands that earlier expansionism had bequeathed to him of strategic overstretch. Borders – of one kind or another – played a significant part in his policy.

And it all started 1,900 years ago this summer.

The rest is history...

Over the next generation, the Roman frontier shifted north, and then dropped back down to the line of 'Hadrian's Wall.' There it would stay until imperial rule wound down in Britain. Mobile troops were shifted elsewhere. Border regiments increasingly recruited from the locals and became part of the regional landscape. These soldiers probably only realised that imperial rule in Britain had ceased in the early fifth century, when the pay stopped being delivered. Then they morphed into the armed support for local tough guys, who fought it out for dominance once imperial government broke down. By this time, it was more like 'Palermo of the Mafia' than the 'imperial projects' of the past. And from them and their like emerged the petty kingdoms of early medieval Britain.

This talk of northern borders raises questions about the complex mosaic of peoples who made up – and make up – the inhabitants of the British Isles. It also reminds one of the changing power-dynamics of the relationships between them over time.

Today it is sometimes assumed (in southern Britain) that Hadrian's Wall is the border between England and Scotland. It isn't. Hadrian's Wall was made irrelevant by the end of imperial rule in the fifth century. The contested lands – between what would eventually become England (effectively known as this by the 10^th century) and the Picts, Scots, Welsh-speaking Britons, and Norse, of what became the kingdom of Alba and (by the 12^th century) Scotland – shifted north and south of it. At times, English kings ruled in Lothian and kings of Alba/Scots ruled in Cumbria.

For large parts of the Middle Ages, the demographic and economic strength of England allowed its rulers to attempt to impose themselves on Scotland – and many Scots to fiercely resist this. Unlike Wales – which succumbed to English aggression in 1282, when Llywelyn ap Gruffudd, Prince of Wales, died in an English ambush – the Scots maintained their independence. Therefore, England is still, at times, referred to as 'the Auld Enemy' in Scotland.

This changed in 1603, when a king of Scots (James) also became king of England and Ireland. Then, in 1707, formal union between England and Scotland went further than a shared monarch. The 'Kingdom of Great Britain' was the result.

Finally, in 1800, the parliaments of Great Britain and Ireland each passed an Act of Union (it became effective in 1801), which united the two kingdoms and created the 'United Kingdom of Great Britain and Ireland,' with one parliament (in London).

It was at this point that the modern Union Flag came into existence with the addition of the diagonal red cross of St Patrick. It also explains why it is possible to fly a Union Flag upside down. The Union Flag is not symmetrical. On the side nearest the flagpole the white diagonal should be thicker above the red diagonal, at the top left-hand side, in order to show the precedence of Scotland over Ireland in terms of when union occurred.

Wales, it should be noted, has no representation on the national flag. It was subjugated by force. This month is the anniversary of the death of Princess Gwenllian, the only child of Llywelyn ap Gruffudd, on 7 June 1337. At just one year old, she had been seized by the victorious England and placed (imprisoned) in the Gilbertine Priory of St Mary, at Sempringham, Lincolnshire. She was never allowed to leave its walls.

In 1921 Northern Ireland was established, when Ireland was partitioned by the Government of Ireland Act 1920. The next year the Irish Free State came into existence. In 1937 it became the Republic of Ireland. The modern 'United Kingdom of Great Britain and Northern Ireland' is the result.

Borders, flags, jubilees – and the future of the UK

All of these, apparently disparate, things came to mind as I was hanging up the Union Flag bunting over the long weekend of the Platinum Jubilee of Queen Elizabeth II. It occurred to me, that there is a very real possibility that this will turn out to be the last jubilee celebrated in the United Kingdom. There will, in time, be a coronation. But a lot of evidence suggests that, by the time any kind of future jubilee is celebrated, the union will probably be consigned to history.

The simple reality is that loyalty to the Queen does not necessarily equate to enthusiasm for the union over which she presides. On 1 June, the day before the start of the Platinum Jubilee celebrations, the latest monthly polling averages on the question of Scottish independence revealed 'No' to have a 5% lead over 'Yes.' The 'No' side stood at 52.5% and the 'Yes' side stood at 47.5%. This compares with the position in the 2016 Independence referendum, when 55.3% of Scottish voters opposed the plans for an Independent Scotland, and 44.7% voted in favour. The difference has shrunk.

Does this mean that Scotland is slowly making its way to the exit door from the union ('Scexit')? Maybe. Although it is hard to know, as in January this year the two sides were tied at 50/50 according to polling data. The important thing to note, perhaps, is that independence as an issue does not go away. And, in a nation that voted against Brexit (62% voted 'Remain'), little has happened since 2016 to enamour Scots regarding a decision that was largely driven by England (assisted by Wales). Also, when the UK government holds only 6 Westminster seats north of the border, and the main opposition party only 1 seat (out of a total of 59 such seats), Westminster can seem part of a foreign nation.

In Northern Ireland (where 55.8% voted 'Remain') the slow-burning crisis over the NI Protocol and the issue of borders (that phenomenon again) has increased tensions to a very significant degree. In that situation, the possibility of a hard border with the Irish Republic (which would break the Good Friday Agreement and anger nationalists) versus a kind of border down the Irish sea (which infuriates unionists) has been a 'Brexit dividend' that threatens a return to historic violence. The Border Poll, so feared by the unionists, inches closer.

Brexit (whatever one feels about it) – with its slogan of 'Take back control' of borders – may, in time, lead to more borders being established within the British Isles than existed in 2016. And with that, the end of the union that has been in place since 1707 and 1801. As I ate the last of the scones and folded the Union Flag bunting, I wondered if the emergence of future borders may require the purchasing of a different flag design.

Borders are such complicated things. I think Emperor Hadrian would agree with that. Issues of national identity can be so difficult to resolve amicably. Princess Gwenllian would certainly concur.

Martyn Whittock is an evangelical historian and a Licensed Lay Minister in the Church of England. As the author, or co-author, of fifty-four books, his work covers a wide range of historical and theological themes. In addition, as a commentator and columnist, he has written for several print and online news platforms; has been interviewed on radio news exploring the interaction of faith and politics; appeared on Sky News discussing political events in the USA; and recently has been interviewed regarding the war in Ukraine, including its religious dimensions. His most recent books include: The Secret History of Soviet Russia's Police State (2020), Daughters of Eve (2021), Jesus the Unauthorized Biography (2021), The End Times, Again? (2021) and The Story of the Cross (2021). He has just completed Apocalyptic Politics (2022 forthcoming), which examines apocalyptic beliefs driving political radicalization across global cultures.