The Spanish Civil War broke out in June 1936. The Republicans were loyal to the left-leaning Popular Front Government of the Second Spanish Republic, while the Nationalists were far-right conservatives, monarchists and fascists who mounted an insurrection. It was a fight between democracy and dictatorship, as well as between fascism and communism.
The International Brigade consisted of military units set up by the Communist International to assist the Republicans in the civil war. It existed from 1936-38 and around 50,000 members from around the world joined its ranks. Most were members of the Communist Party or were Jewish, and they predicted the religious persecution that would follow if the Nationalists were to win.
Robert Macdonald came from a working-class family from a little village called Auchinairn, about four miles outside Glasgow. He was at Glasgow University when he became a member of the Communist Party. He had very strong beliefs in social justice and so he joined the International Brigade and prepared to travel to Spain to fight with the Republicans. He and a few of his comrades travelled to Marseilles, where they secretly boarded a cruise ship, the Ciudad de Barcelona, along with more than 200 other Brigadistas, and they set sail for Spain.
At about 6pm on the afternoon of 30 May 1937 the ship was just 400 metres off the coast at Malgrat, north of Barcelona. The submarine, General Sanjuro, fired two torpedoes. The first one missed, but the second exploded in the engine room. More than 200 died, many of whom were cruise passengers. Around 65 Brigadistas died, but because of the secrecy surrounding the voyage not all of their names are known.
This is from the account of Brigadier Robert C. Martin, “We went by sea to Barcelona. We were told that we could not go by land because the anarchists were at the border and would shoot us. Our boat was sunk by a submarine — it was said to be an Italian submarine. When the torpedo hit the ship I went over the side and was picked up by a fishing boat after twenty-five minutes in the water. Sixty-five men went down with the ship. I was deeply stirred by the way in which the boys who were left on the boat sang the Internationale as the ship went down. Among them was my friend, Robert MacDonald, who enlisted me.”
If the Republicans had won the Spanish Civil War, then very possibly World War 2 would never have happened.