Scottish independence: How 16th century Protestant Reformation played key role in Union of Scotland and England, and now offers insights into whether they will divorce – Professor Peter Marshall

What will history books make of the current Tory leadership contest, and its significance for the state of the British Union?

Will it matter that Liz Truss, without any apparent sense of irony, branded the First Minister an “attention-seeker”, or that Rishi Sunak seemed to think Darlington was somewhere in Dunbartonshire?

Historians are notoriously bad at forecasting the future. We deal with patterns revealing themselves only gradually and retrospectively, while politics, and political promises, are breathlessly and depressingly short-term. John Maynard Keynes famously remarked “in the long run we are all dead”, but that suits historians just fine. If not quite our bread and butter, the dead are certainly our data.

Perspectives from history can’t predict the date of Indyref2, nor how it is likely to turn out. But they can help clarify what Britain has meant in the past, even as we try to decide what it might mean in the future.

It is not much remarked on in current debates, but ‘Britain’ is a distinctly ideological project, born at a particular historical moment: the Protestant Reformation of the 16th century.

Henry VIII’s break with Rome, we are often told, was the ‘first Brexit’. It wasn’t. England exited, but Henry’s nephew, Scotland’s James V, reacted by stiffening his stance as a loyal son of the Pope and European church. Traditional Anglo-Scots enmity was sharpened by religious rivalry, especially after James offered refuge to leaders of an English Catholic rebellion, the Pilgrimage of Grace.

Religion was a factor in the war that broke out in the 1540s, leading to the death of James, supposedly of a broken heart, his army was defeated at Solway Moss.

A group of translators hand a King James Bible to King James I and VI, circa 1611 (Picture drawn by George E Kruger/Hulton Archive/Getty Images)

In its aftermath, plans for an Anglo-Scots union took concrete shape. Henry hoped to neutralise any threat from Scotland by betrothing his son Edward to James’s infant daughter, Mary – and to terrorise the Scots into agreeing through a policy of military incursion, known euphemistically since the 1800s as the “rough wooing”.

This ingenious solution never came to fruition, though it was pursued energetically by the reformist regime around Henry’s successor, the young Edward VI. A union of crowns would secure Protestantism’s future in both realms. The Reformation, and the associated ‘British’ strategy, came dramatically off the rails with Edward’s premature death in 1553.

His half-sister, Mary Tudor, ruthlessly persecuted English Protestants and renewed the alliance with Spain through marriage to Philip II. Mary, Queen of Scots, married another Catholic monarch, Francis II of France, while her French mother, Mary of Guise, regent in Scotland, made a fairly good job of suppressing Protestantism there.

The proliferation of powerful Catholic Marys provoked the exiled John Knox’s notorious expression of political misogyny, "The First Blast of the Trumpet Against the Monstrous Regiment of Women”.

Britishness, in a sense, was forged in Calvinist Geneva during the Reformation’s darkest days. Scots Protestant exiles like Knox found common ground with English ones, and realised their commitment to ‘the Gospel’ meant more to them than narrow national sentiment.

This was not the mindset of Elizabeth I, the cautious semi-Protestant who ascended the English throne in 1558. But it animated important figures around her, like the chief minister, William Cecil.

In 1560, pressure from Cecil persuaded a reluctant Elizabeth to intervene militarily in Scotland, preventing its infant Protestant Reformation being crushed by the French. Thus started the chain of events leading to the overthrow of Mary, Queen of Scots, her flight to England, imprisonment and eventual execution.

The union of crowns was achieved, in 1603, by the arrival on the English throne of Mary’s Protestant son, James VI. James was an enthusiast for the novel concept of ‘Great Britain’, though the great majority of his subjects, north and south of the border, were not.

Yet the political equation behind his succession is clear enough. The English governing classes were reluctantly prepared to accept a Scots candidate for the throne in preference to any potential Catholic one – something that would have been quite unimaginable even half a century earlier.

The subsequent progression, over the course of a long and eventful 17th century, from the union of crowns to political union was similarly driven by a shared Protestant identity, even alongside the enduringly different forms taken by the Churches of Scotland and England.

This helps explain why the Anglo-Scots union ‘took’, while the Anglo-Irish one never really did. More than any other factor, it was the spectre of Jacobitism – the prospect of the return of the deposed Catholic Stuarts – that in 1707 persuaded the parliaments of England and Scotland to enter what was at first a distinctly loveless marriage.

Affection developed over time, in large part due to the shared task, through a century and more of intermittent warfare, of confronting and containing Catholic France.

Commitment to Protestantism, or any form of organised religion, is a minority pursuit in both England and Scotland today. Faith is not an issue in current independence debates, though there may be a cultural echo of past allegiances in the fact Scottish Catholics were more likely than Protestants to vote ‘Yes’ in 2014.

One of the principal historical underpinnings of Britishness has, then, ceased to be meaningful to most citizens of the UK. Others have gone too – a co-dependent industrial economy, for example, along with shared exploitation of a global empire.

None of this makes the break-up of the Union inevitable, or even probable. Married couples are not predestined to divorce when their children grow up and leave the family home.

But their relationship needs rejuvenating on a basis of more than shared memories. A task for future historians of Britain will be to analyse how – if at all – this was achieved, and whether supposedly unionist politicians helped or hindered the process.

Peter Marshall is professor of history at the University of Warwick, and winner of the Wolfson History Prize 2018 for his book, Heretics and Believers: A History of the English Reformation