The one phrase most likely to have been in the heads of those who went to fight for an Irish republic in 1916 came from the writings of Theobald Wolfe Tone. Patrick Pearse never tired of plucking it out as the essence of the radical nationalist movement: "We need not restate our programme; Tone has stated it for us: 'To break the connection with England, the never-failing source of all our political evils' . . . "

The rebels were a disparate bunch, but this was what united them: breaking the connection with England.

What did they mean by that? Primarily, the establishment of an independent, sovereign Irish state, outside the United Kingdom and the British Empire. But the evils of which England was the never-failing source were not just directly political. They were also cultural, economic and demographic.

Ireland, in order to be a sovereign nation, would need to be, in Douglas Hyde’s famous formulation “deanglicised”. The worst insult in nationalist circles was “Shoneen” – little John, a mini-me version of John Bull.

The cultural connection with England would be broken by replacing English with Irish as the vernacular language, by replacing “garrison games” like soccer, rugby and cricket with Gaelic games, and by replacing effete tea dances with the vigorous and virtuous céilí.

And the economic connection would be broken. England had retarded and reformed the Irish economy by shaping it to serve the needs of the “mainland”. A free Ireland would develop its own resources and become a modern industrial power in its own right. It would, in particular, provide work for its own people, ending the scourge of mass emigration and population decline.

Economic independence would thus also break the demographic “connection with England” – the flow of Irish people to the industrial cities of the neighbouring island.

Breaking the connection with England

A century on, as we face Brexit and the biggest change in relationships between Britain and Ireland since the revolutionary period, we might draw some calming lessons.

The violent upheaval of 1916-1923 did, in some respects, break the connection. But even in political terms the breach was far from complete. One anti-Treaty poster from 1922 turned Tone’s formula back on the founders of the Irish Free State: “Fight to break the connection with England,” said Tone. “Wrong,” said Michael Collins, “fight to establish that connection.”

And the other great acts of severance, the snapping of the cultural, economic and demographic connections, didn’t really happen.

Even at the level of political and legal forms the connection remained strong. The system of government adopted by independent Ireland had some innovations, most obviously the adoption of a written constitution and of proportional representation. But the Irish parliamentary system was essentially the Westminster model with Gaelic names.

The Civil Service was initially staffed by people trained in the imperial bureaucracy, and many of the same attitudes and procedures were deeply embedded in the new State. English common law remains in force in Ireland.

The big cultural project of deanglicisation, the replacement of English with Irish as the day-to-day language, was an almost complete failure. More broadly, the nationalist desire to replace one culture with another came up against the Irish habit, when faced with incompatible alternatives, of choosing both.

The GAA did indeed thrive, but it was not really at the expense of “alien” English sports. Even the embodiment of Gaelic nationalism, Éamon de Valera, confessed to the British ambassador in 1967 that he “always preferred rugby” to the GAA.

Dev the rugby fan

Dev, at least, understood quite well that when it came to sport

being deanglicised was a complex business. He opposed the GAA’s ban on its players taking part in “foreign games”, noting, rightly, that “many who play Gaelic football would, if the ban was lifted, be inclined to play rugby also.”

This duality applied to almost every aspect of day-to-day Irish culture. A passion for Manchester United did not exclude a love of Cork hurling. Readers who bought Dev’s Sunday Press outside the church gates after Mass were not beyond slipping a copy of the News of the World beneath its folds.

Coronation Street made as much sense to Irish viewers as The Riordans did. Kids who screamed at The Beatles were also happy to tune into The Dubliners or The Chieftains. The ease with which figures like Eamonn Andrews and Terry Wogan could insinuate themselves into the intimacies of English life suggested that the Irish Sea was, culturally speaking, a much narrower gulf than the 1916 rebels would have wished.

The economic connections were not broken, either: until we joined the European Economic Community, in 1973, the Irish economy was a minor moon locked in the orbit of the much larger English planet.

Even that momentous change was a function of Ireland’s dependency: Ireland applied to join the EEC in 1961 because the UK did so, and it was eventually admitted on Britain’s coat tails. And even though membership of the EU and investment by US-based multinationals have transformed the Irish economy, the English market is still far more important than any other for indigenous Irish firms.

The failure to break the economic connection also meant that large-scale Irish emigration to England was hardly affected by Irish independence. One of the great historical ironies, indeed, is that it was at the end of the first decade of Irish independence that Britain, source of all our evils, replaced the US as the primary destination for Irish emigrants.

By the 1950s 80 per cent of Irish emigrants were going to Britain. The scale of the exodus was staggering: about three of every five children growing up in the 1950s were destined to leave the Republic.

If we think of Irish people, as opposed to some abstract notion of Ireland, much of the postindependence experience can be seen as a process not of deanglicising but of reanglicising.

The strange death of Anglophobia

The idea of Anglo-Irish relations became quite literal: most Irish people had, and still have, close relatives who are both Irish and English. From the 1980s onwards this new Anglo-Ireland found its voice in rock groups like The Smiths and comedians like Kathy Burke and Steve Coogan, in Martin McDonagh’s plays and in Jack Charlton’s soccer team.

The failure to "break the connection" can be literally dramatised. Irish actors can play English characters without much strain: Brendan Gleeson, for example, could play both Michael Collins (in The Treaty in 1991) and Winston Churchill (in Into the Storm in 2001) with complete conviction. (Aidan Turner, who plays the archetypal romantic Englishman in Poldark, has remarked of the English accent he uses for the role that "for a lot of Irish actors it's a second tongue".)

Conversely, actors often thought of as typically English can be brilliant in Irish roles: think of Judi Dench in Philomena or Julie Walters in Brooklyn. (It helps, of course, that both women have Irish-born mothers.)

This is not to say that there are not lingering vestiges of condescension on the one side and belligerent hypersensitivity on the other. Anglo-Irish relations reached some very low points during the Troubles, and the anti-Irishness that came to the fore in England after the IRA’s atrocious bombings of pubs in Birmingham and Guilford tapped into a deep reservoir of inherited prejudice.

But it is also true that one of the big underlying stories of Ireland in the past 20 years is the strange death of Anglophobia. It is one of those slow, creeping changes that became fully apparent only through an absence. It came to full consciousness during the visit of the British monarch, Queen Elizabeth, to the Republic in May 2011.

There was, of course, an enormous security operation to keep protesters away from her highly charged laying of a wreath at the Garden of Remembrance in Dublin. But where was the mass of protesters? For anyone with a sense of history it was astonishing that no more than a few hundred had gathered to shout at the old woman who embodies the never-failing source of all our political evils.

For most Irish people the royal visit prompted reactions that ranged from healthy indifference to benign curiosity, a sense of historic occasion or outright fawning. Hatred was a niche emotion.

The death of Anglophobia had its immediate causes, undoubtedly, in the Northern Ireland peace process. That process was made possible by the realisation of both governments that they had to work hand in glove if they were to deal with a shared, chronic and debilitating problem.

The evolution of this joint approach was in turn made possible by the experience of Irish and British politicians and diplomats in working closely together within the context of EU. This high-level amity did trickle down into popular attitudes.

Irishness = non-Englishness

But much larger-scale processes were at work, too. Modern Irish nationalism evolved in opposition to England and Englishness. It therefore took the form of a negative image of what it was against. Even republicanism was valued less for its positive meaning than for being the opposite of the English system of government.

As the historian Michael Laffan has put it of the radical nationalism of a century ago: “Just as the appeal of the Irish language was enhanced by the fact that the British people spoke English, so Ireland must be a republic because Britain was a monarchy.”

Similarly, England’s official Protestantism made it obvious that the Irish state would have a special place for Catholicism. England’s urban industrialism made Irish rural pastoralism not a reality of underdevelopment but a rebuke to the old enemy.

These oppositions gradually faded with the belated modernisation of Irish society. Religion became a less important marker of national identity in both societies, and the rise of English Catholicism blunted the sharp edges of the historic divide.

Ireland’s increasingly industrial (or postindustrial) society made the old rural/urban contrast more tenuous. It is not accidental that so many Irish urban shopping streets look exactly like their counterparts in Slough or Coventry: Irish consumer tastes are virtually indistinguishable from those of the English.

Nor is it accidental that British companies stopped dubbing their TV ads with Irish accents for Irish channels: the Irish are so used to being part of the British market that they scarcely notice any more.

The rise of English nationalism

Depending on one’s political orientation, these failures to break the connection between Ireland and England are either a gross betrayal of the men and women of 1916 or an expression of the inevitable realities of sharing an archipelago with a neighbour that is bigger, more powerful and much more influential in its global reach.

But what’s interesting about them in the context of Brexit is that they feed into a complacency that might in fact be misplaced.

We have a century’s worth of proof that even a violent nationalist revolution left many key aspects of the Anglo-Irish relationship intact. And so, we might conclude phlegmatically, an observer in 2216 will also look back on the British upheavals of 2016 and say that, whatever else they changed, the political, economic, cultural and demographic connections between Ireland and England went on pretty much as before.

And maybe they will. The basic facts of geography won’t alter, and the leading Brexiteers in the British government keep repeating that nothing will change in the relationship with Ireland.

But it might be a mistake to be too complacent. There are several factors that seem genuinely new and that might have profound consequences.

One is the rise of English nationalism, a force previously sublimated in the empire and in notions of Britishness but now unleashed and unpredictable.

Another is the way that Brexit unsettles not just relationships across the Irish Sea but also the relationships between all the polities that make up “these islands”: what, for example, would it mean if Scotland were to remain within the EU alongside Ireland?

A third is the question of the Border. For all the reassurances that there will be no hard border, the prospects of a demographic and economic frontier are very real. And then there is the simple question of shared EU membership itself. If being together in the EU brought Ireland and Britain closer, will British exit from the EU drive them apart?

It is by no means impossible that events will unfold in such a way that Ireland will be forced to choose between being within a British sphere of influence and remaining in the EU.

It says much for the complications of the relationship that, although the founders of the State would have jumped at this chance to finally break the British connection, their descendants would find the choice an agonising one.

Britain and me: Share your views

We want to know how you feel about Britain today.

– It’s home to 600,000 Irish-born people and is Ireland’s biggest trading partner. We devour British TV, buy British music, laugh at British comedy. But Irish people’s relationship with Britain is a complex one.

– Do we still cling to the 800-years-of- oppression idea? Can we bring ourselves to cheer for England on the sporting field? Has the vote for Brexit turned everything sour?

– Describe your relationship with Britain in 500 words or less, and we will publish the best articles online and in the print edition of The Irish Times.

Send your thoughts to britainandme@irishtimes.com