Catholic Emancipation deserves its place among the great moments in the long constitutional development of the United Kingdom, but each year it passes with remarkably little notice. Perhaps more fuss will be made when the bicentenary arrives in 2029, but last year when Sir Edward Leigh MP asked Labour ministers what they were cooking up for that anniversary, the Government admitted it had ‘no specific plans’ to mark the occasion.

This is a missed opportunity. Far from being a mere bit of legal tinkering to sort out a troublesome minority, the Roman Catholic Relief Act that received royal assent on this day in 1829 reshaped the relationship between the state and believers not just in the United Kingdom but across what is now the modern Commonwealth. To the extent that civil and religious liberties are today enjoyed by people from Vancouver to Karachi, it is in some sense thanks to this achievement and the man arguably most responsible for it: Daniel O’Connell.

O’Connell, for his part, was renowned across Europe for the scale of his accomplishment. Through the Catholic Association he had created a form of disciplined mass political organisation that was entirely novel for the time, when Metternichian reaction reigned across the chancelleries of the continent, suspicious of any popular political action. O’Connell proved that it was possible to mobilise large numbers of people – many of them dirt poor and excluded from any real participation in political life – and forge them into a coherent force capable of applying pressure on the Government of the expanding British Empire. It raised funds, coordinated messaging and translated popular sentiment into political results – all peacefully and without revolutionary violence.

Through his victory in the Clare by-election of 1828, O’Connell laid down the gauntlet to the Government by forcing it to make a choice: change the law and admit him as a legitimate Member of Parliament, or continue to exclude him and risk a wider crisis. It was the sober assessment of sound conservative men such as Robert Peel and the Duke of Wellington that chose compromise instead of confrontation. This law was secured thanks to the conservative instincts of the Duke of Wellington’s administration, realising that – while instinctively opposed – it was now time for Britain’s constitution to undergo one of its evolutionary acts: to bend instead of break. The ‘Act for the Relief of His Majesty’s Catholic Subjects’ did not establish full equality in every respect, but made it possible to participate fully in the legislative life of the country without being forced to express adherence to the established Church.

The rejection of violence and the instinct to operate within constitutional means were central to O’Connell’s politics. It was not merely that violence was imprudent and counterproductive, but that mass mobilisation – if strictly disciplined and shown to be sustainable – could compel change without any of the orgies of revolutionary bloodletting Europe had seen since the advent of the French Revolution. O’Connell also rejected the class-based divisions that nascent socialists were already preaching. His own social background was among the ever less landed Catholic gentry who had faced generations of constant economic pressure from the penal laws of Ireland’s Protestant Ascendancy. The mass mobilisation of the ‘monster meetings’ was accompanied by O’Connell’s skilful coordination of the Catholic peerage of Ireland and England to help influence and reassure their aristocratic confrères.

Why has O’Connell’s achievement – heralded across Europe at the time – been so diminished over time? Part of the answer lies in the trajectory that Irish nationalism took. Later movements embraced both republicanism – which O’Connell never endorsed – and what is euphemistically termed the ‘physical force tradition’. Even a near-century later, O’Connell’s success posed an implicit challenge to Irish republican violence. If Emancipation could be achieved through peaceful, constitutional means, what did that say about the necessity or alleged inevitability of armed struggle? It is hardly surprising that, upon the re-establishment of (partitioned, admittedly) Irish statehood by the perpetrators of that violence and their inheritors, the practicality of O’Connell was de-emphasised and the romantic sacrifice of the Easter rebels was enshrined in the public pantheon instead.

There is another reason for the mental sidelining of O’Connell. The creation of the Irish Free State sparked a separation of historical narratives in public memory. Irish history became, increasingly, the history of a distinct nation state and its struggle towards achieving freedom. British history continued along its existing lines of an English-dominated but multinational Union that, through empire, was effectively the first global power state. Despite centuries of shared – if usually involuntary – existence, Ireland was written out of the British story except as an occasionally irritable sideshow. Emancipation, rather than being central to the long and organic evolution of Britain’s constitution, was treated as a mere concession to Ireland. Neither state has properly integrated this moment into its sense of historical memory.

There also lingers a hint of regret. Had Emancipation accompanied the Act of Union in 1800, the United Kingdom of Great Britain and Ireland would have had a much stronger foundation. There had been a widespread expectation that ‘Catholic relief’ would soon follow the Union – one of the central reasons the Orange Order rigorously opposed Unionism at the time as a threat to the position of Ireland’s Protestants. The failure to achieve Emancipation swiftly meant that the Union’s foundational decades were ones in which the majority of the Irish population faced exclusion and disappointment. This fostered distrust and entrenched division, ensuring that the Union began its life under a shadow that proved difficult to dispel.

The story matters. Emancipation was not a narrow sectional interest for the United Kingdom’s Catholics. It established the practice – if not yet the full theory – that the state would no longer sustain a system of systematic exclusion based on religious identity. This principle only deepened and expanded over time, shaping the political culture of the United Kingdom at home and the development of its many post-colonial successor states across the Commonwealth. In 1932, Australia’s Jewish governor-general used a Protestant bible to swear in the country’s newly elected Catholic prime minister. While barely remarked upon at the time, that scene would have been unimaginable without Emancipation.

For Catholics, this is an inheritance that ought to be more consciously and openly recognised. For other religious minorities, it is part of the same lineage. The liberties that are now often taken for granted were by no means inevitable. They were proposed, contested, resisted and, in the end, secured through political action of a particular kind. Anniversaries offer an opportunity to recover perspective. Catholic Emancipation was one of the decisive constitutional changes of the 19th century that still affects our everyday lives in the 21st. O’Connell was its principal architect, but not its only one.

The 19th and 20th centuries offer innumerable examples of revolution, oppression, war and violence that the United Kingdom largely managed to avoid, or at least lessen, in its domestic sphere. In 1829, a unique constellation of statesmen and operators laid a foundation for a more peaceful, stable and free society in which Catholics – and indeed many others – could flourish in freedom. Remembering this is not an act of nostalgia, nor a time to reopen settled questions, but to recognise with greater clarity the achievement of our predecessors and how the political order we live in came to be. At a time when we seem mired in increasingly ill-managed decline, it is also a reminder that we still have things for which to be grateful.