Del Berg nearly died around 10 a.m. one sunny day in August 1939.

The 23-year-old American was staying at a monastery outside Valencia, Spain, when Italian bombers flew over and dropped their payload. The bombs were aimed for a nearby rail depot, but they hit the monastery instead. Berg, who was on the second floor, and the men he was with frantically climbed downstairs on a pipe. Berg was last, and it was only when he’d gotten down he realized his shirt was soaked in blood. Shrapnel had struck his liver.

That piece of shrapnel was still in Berg’s liver when he died—more than 76 years later, on Sunday at his home in California. He was 100.

Although the bombardment was not intended for Berg and his compatriots, the Italians wouldn’t have shed any tears. Mussolini’s air force was flying sorties in Iberia on behalf of General Francisco Franco, the Fascist fighting for control in the Spanish Civil War. Berg was there as a member of the Abraham Lincoln Brigade, a group of idealistic, often far-leftist Americans who took up arms on behalf of the doomed Spanish Republic. He was believed to be the last surviving member of the brigades.

Around 3,000 young men volunteered for the fight, slipping surreptitiously into Spain. About 800 of them were killed. The war ended in 1939, with Franco victorious. He would go on to lead a repressive dictatorship until his death in 1975. Some of the brigadiers who returned led fairly straightforward mid-century American lives, but not Berg. After returning to the United States in 1939, he was drafted by the U.S. Army and sent to New Guinea. Discharged in 1942 because of his wounds from Spain, Berg promptly joined the Communist Party USA, and led a life of activism throughout his life.

Berg was an old-school leftist—the type who came by his politics not from theory but from life. Born Delmer Berg in December 1915, his father was a tenant farmer. “I was born into a very poor farm family in Southern California.” he told the Anderson Valley Advertiser in 2013. “We lived near Modesto, and I became a radical early on in life.”

A dishwasher with a union card, 21-year-old Berg was walking down a street in Hollywood when he saw a sign on the side of a building:  “Friends of the Abraham Lincoln Brigade.” He walked in and asked to go to Spain. They explained they couldn’t directly send him, but they helped direct him. What followed was a circuitous process involving various offices, unmarked doors, and a dour, crippled World War I veteran. Eventually, Berg took a cross-country bus to New York, and then he and other volunteers took an ocean liner to Paris followed by a broken-down bus to near the Spanish border.

In Spain, Berg helped install communication lines for anti-aircraft batteries. The war is considered a test-run for the heavy bombardment of the Second World War, and it afforded Adolf Hitler and Mussolini a chance to try out tactics on behalf of Franco. The Soviet Union aided the Republicans. (The methods were still a little rough, which is one reason the monastery was struck: “‘If you want to be safe,’ we used to say, ‘go to where the fascists want to bomb.’”) Berg also fought in the Battle of the Ebro, the war’s biggest battle.

He sometimes claimed political naïveté about the conflict—“I didn't know a damn thing politically. We were just kids. We wanted to do something to help the Spanish people”—but back in the states, Berg continued to espouse leftist and radical causes. He was vice president of his local NAACP chapter—at a time when he was reportedly the only white member. He worked with Dolores Huerta and the United Farm Workers. Later, he protested nuclear weapons and the Vietnam War.

During the McCarthyite 1950s, Berg said federal agents questioned his family and friends, but they didn’t ever question him directly, which he attributed to the place he lived: a trailer between a Pentecostal church and a whorehouse on the wrong side of the tracks in Modesto. “They hesitated coming to the black community,” Berg told The Union Democrat in 2007, but he did not.

In 1966, the House Un-American Activities Committee wanted to question him. “They could never find me to serve a summons,” he boasted in 2012 to The Volunteer, an Abraham Lincoln Brigade veterans’ paper. He said that the two proudest moments of his life were “when I was elected vice president of the local NAACP, and when one of my grandsons was valedictorian at his Oregon high school graduation and said in a newspaper interview, ‘My grandfather is my inspiration. He’s a Communist!’”

Berg remained dogged in his political pursuits up until the end of his life. In 2007, he told The Union Democrat that his hearing was making it hard for him to go to meetings and speak out on the topics he cared about—including fighting for national health care and against the privatization of Social Security—but that he had to keep it up: “Sometimes, if I don’t do it, no one else will.”

In 2014, a reporter for People’s World, the digital offspring of the old Communist paper the Daily Worker, visited Berg at his self-built home. The 98-year-old demanded to hear what had happened at the last AFL-CIO convention. In an interview with The New York Times last year, he lamented his unfinished work. “It bothers me a little that at 99 you’re going to die any minute, because I have a lot of other things I want to do,” he said.

Yet it’s hard to imagine many people getting quite so much out of life as Berg did in his century. And with his passing marking the end of the survivors of the Abraham Lincoln Brigade, it’s a little harder to imagine the horror of the Spanish Civil War.