They came from across Ireland and fought against fascism in the 1930s as part of the International Brigades.
Joe Boyle had to send home for money
At the weekend, their role in the fight against Franco on the side of Spain's ousted republican government was marked in Belfast.
A display of memorabilia and photographs relating to the defeated republican side is on display in the Linen Hall Library.
It is thought 78 of the 2,000 left-wing idealists from Britain, Ireland and the Commonwealth who fought against Franco came from Northern Ireland.
A sculpture to the men, 20 of whom died in battle, was unveiled in Writers' Square, opposite St Anne's Cathedral.
The story of one who survived the war is told in a poignant scrapbook in the museum exhibition.
It features a 1936 telegram from Joe Boyle to his family pleading for £32 to be sent to allow him and Fred McMahon, also from Belfast, to make their way home from Portugal after spending time as a prisoner.
He is described as a pacifist who went to war, serving as a volunteer ambulance driver because he did not want to kill.
It is estimated that 500,000 people died in the three-year conflict.
Images form part of the library display
Ciaran Crossey, researcher for the International Brigade Commemoration Committee told the News Letter men from both religious backgrounds had fought, united by their politics.
"Six originated from the Shankill area, and one of these appeared to be a man with a Catholic background," he said.
"Essentially, these men were activists under the umbrella of the Labour movement and it is a safe assertion that all traditions were represented."
Irishmen also fought on the side of Franco, mostly members of the Blueshirts who joined up with the Franco forces as part of Eoin O'Duffy's 700 strong brigade known as la bandera Irlandesa. The last living member reportedly died in 2007.