One of the mysteries of the hidden history of Belfast's Protestant working class has been what happened to those Mauser rifles smuggled into the city during the Home Rule crisis.
The German-supplied weapons occasionally kept turning up during the decades after the First World War, partition, the Second World War and even the Troubles.
In the early-1990s, the old weapons from the Kaiser kept cropping up in the most unusual places. During redevelopment work in the York Street-Tigers Bay area during the years before the ceasefires, a few old Mausers were discovered hidden in the chimney breast of a house being demolished at Brougham Street.
Clearly, many of those who had agreed to store the original UVF's rifles that were to be used in the event of civil war were either long dead, or their descendants had forgotten these secret arsenals existed.
Around this time, journalist Jim Cusack and I were researching a history of the modern UVF, which meant one of our obvious points of contact was the founding father of the reconstituted loyalist movement, the late Gusty Spence.
During one of many interviews with the Alpha and Omega of Ulster loyalism, we asked Spence about the Brougham Street find and what had happened to all those thousands of now-antiquated rifles Lord Carson's underground army had imported.
Knowing my own family's Left-wing background, Spence had a twinkle in his eye when he informed me that some of those guns ended up being sent to the republican side in the Spanish Civil War.
Neither Jim nor I were able to verify, or find further evidence, that weapons originally exported to destabilise the British empire from a German imperialist would end up in the hands of democrats, socialists and communists fighting Hitler's allies in Spain.
Among those who was also intrigued by what we wrote about Spence's claim was the Belfast socialist activist Ciaran Crossey. I don't know if Ciaran ever established a plausible link between Carson's Mausers and arms to the Spanish Republic, but it is to his and his research team's credit that they have highlighted an arguably more important connection between Protestant working-class Belfast and the cause of democratic Spain.
On Saturday, at Shankill Library, they unveiled a plaque celebrating the role of seven local men who travelled thousands of miles in the 1930s to defend Spain against Franco's fascist rebellion. Four of the men – William Beattie, Bill Henry, William P Laughlin and Harry McGrath – were killed in action.
What all seven had in common was that they were British Army veterans, the survivors later joining Allied units (including the Canadian forces) during the Second World War. Just as significantly, at home they were trade unionists, communists or members of the old Northern Ireland Labour Party.
It is heartening to see such a project on the Shankill Road which rediscovers the area's relatively unknown, unreported progressive history and gives a nod to Ulster Protestantism's socially radical past.
The event to mark men's fight for Spanish democracy was accompanied by a lecture from Dr Conall Parr, entitled Radical Protestants From The 1930s To The Sixties. But such radicalism, of course, stretches back over centuries and its tradition played a role in shaping world history.
It was Belfast, after all, that can proudly boast being the first city of the empire to actively oppose slavery.
The city's Presbyterians, especially those based around First Rosemary Street Church, organised the first boycott of sugar, because it was "made in blood" from the slaves. They were, in fact, the pathfinders for the anti-slavery movement, which became a national and international issue – thanks later to William Wilberforce.
The Protestant tradition of dissent, individual free thought and the role of one's personal conscience was the cornerstone of the United Irish movement, although, of course, the 1798 rebellion tragically degenerated into sectarian blood-letting and revenge killings in many places, such as Wexford.
Yet even outside the north, in the area in and around Dublin, some of the descendants of Cromwell's Puritan army played a progressive role in the 18th century.
The Dublin historian and former Official republican, Fergus Whelan, has traced in his recent book, Dissent Into Treason, a direct lineage between some of Cromwell's soldiers, who settled in the city, with the 18th century United Irishmen.
It is a tragic irony that the original 'dissidents' of Belfast and the north in general were the Ulster Presbyterians, influenced as they were by the 'New Light' teachings from the Scottish and European Enlightenments. If the modern-day 'dissidents' on the republican/ nationalist side of the divide really want to pay more than lip-service to the concept of the unity of Protestant, Catholic and Dissenter, they could create some fresh space for more progressive voices on the other side of the peacelines to be heard.
They could do that by heeding these voices and those also from their own communities in declaring lasting ceasefires.