Matías Arranz Aparicio was a Spaniard who fought for the Republic in the Spanish Civil War and survived four years in Nazi concentration camps during the Second World War. He dedicated his life to denouncing Fascism.

Arranz was born in 1914 in Vadocondes, Burgos province, in northern Spain. When he was 19 he moved to Madrid, where the Spanish Second Republic had just replaced the Bourbon monarchy. He became a member of the Socialist union and later joined its militant youth wing.

When the civil war broke out in July 1936 Arranz joined the heterogeneous militia units leaving Madrid to fight General Franco’s advancing columns. Two months later, he was wounded in the arm fighting on the Illescas front, 20 miles south of the capital.

On recovering from his wound Arranz rejoined the struggle and was posted to a unit of the International Brigades. It was unusual for Spaniards to fight with the Internationals but as the war progressed Spanish men were increasingly drafted in to replace the numerous casualties that the units suffered. Arranz fought with the Polish Dabrowski Battalion in the XIII International Brigade and saw action in the major battles of the civil war, including Guadalajara, Teruel and the Ebro.

In early 1939 the Republic collapsed and the Nationalists won the civil war, forcing thousands to flee the country to escape the violent Francoist repression. Arranz crossed the Pyrenees to relative safety in France, where he was interned at the Saint Cyprien refugee camp. Conditions in the open-air sites were very basic and the Republicans suffered from cold, lice and hunger. Many died from contagious diseases. “humiliated us”, Arranz remembered bitterly.

He was able to leave the camp when he enlisted in the French Army. However, French resistance to the German Wehrmacht in the Second World War did not last long. Arranz was captured at the end of June 1940, only weeks into Germany’s offensive, after fighting in the Ardennes and in the defence of Paris.

When France fell the Germans captured many exiled Republican Spaniards and approached Franco to ask whether he wanted them repatriated. The Nationalist Interior Minister, Ramón Serrano Súñer, who was also Franco’s brother-in-law, responded that the exiles were no longer Spanish and that the Nazis could treat them as they wished. As a result thousands of Spanish Republicans were sent to German concentration camps.

In January 1941 the Nazis sent Arranz to Mauthausen concentration camp, 12 miles east of Linz in Austria. Weeks later, he was transferred to neighbouring Gusen and tattooed with the number 10170. The camp was constructed to work “incorrigible political enemies of the Reich” to death. “You arrive through the door, but you will leave through the chimney,” he was told by a German officer before being forced to strip and shower in water at minus 15C (5F).

For more than four years Arranz worked from dawn until dusk on starvation rations, and his survival was a feat of unimaginable endurance. “You could only escape that hell with a combination of strong willpower and luck,” he said. “Twenty people died every day. The first to die were those who constantly remembered their families. I was as resilient as possible and, for months on end, I did not think of anything at all.” Arranz was helped by a painless stomach ulcer that kept hunger at bay. Thousands perished in the gas chambers, while others were taken away on what Arranz called “ghost buses”, never to be seen again.

Arranz remained in Gusen until American forces liberated the camp on May 5, 1945. His ordeal, however, was not over and he remained without a home to return to. Franco was firmly in power in Spain and, in the new climate of the Cold War, the Western powers saw him as a bastion of anti-communism. As a result, Arranz returned to France and settled in the south, near the Spanish border, where he worked as a lathe operator. Here he married a French woman, Ivonne. They had a son and two daughters.

Arranz dedicated the rest of his life to keeping the memory of both the Spanish Civil War and the Holocaust alive. He returned to Mauthausen in 2005 and used his own story to denounce Fascism. He also remained a committed Republican.

Arranz’s wife died in 2000 and he is survived by his two daughters.

Matías Arranz Aparicio, Spanish Civil War veteran and concentration camp survivor, was born on February 24, 1914. He died on August 13, 2008, aged 94