Carrillo’s extraordinary life story paralleled the tumultuous history of 20th century Spain, which included a deadly civil war, four decades of military dictatorship and the return to democracy.
Spain’s El Pais newspaper reported that about 12,000 people had passed through the chapel in Madrid where Carrillo lay in an open casket to pay their respects.
Mourners included Spain’s Vice President, Soraya Sáenz de Santamaría, the Minister for Employment, Fatima Banez, and the Minister for Public Works, Ana Pastor.
One of the last remaining prominent survivors of the 1936-1939 civil war; Carrillo spent 38 years in exile (primarily in France) after his side, the Republicans, lost to the Nationalists of General Francisco Franco.
Perhaps the most controversial incident in Carrillo’s career – one that the right-wing still hold him responsible for – was the massacre of thousands of nationalist supporters during a chaotic evacuation of prisoners from Madrid to a jail nearby called Paracuellos in 1936.
Carrillo denied he had anything to do with the mass killing, and attributed it to the general sense of anarchy in the war-torn city.
However, Paul Preston, a British historian who studied the Spanish Civil War and the Paracuellos incident in particular, declared that Carrillo was not completely blameless.
"Carrillo was an important part in the second phase [of the evacuation], and his many statements that he knew nothing and it was all the anarchists' fault are not truthful," Preston said at a Madrid conference last year.
"This does not mean that Paracuellos is his work alone. He was one, and a very important one of many who did this terrible collective deed."
By the 1970s, Carrillo sought to distinguish Western European Communism from the old Soviet model by founding a movement called ‘Euro-communism.’
He returned to Spain in 1975 following Franco’s death and continued to lead the Communists, finishing third place in the 1977 general election with 9 percent of the electorate.
However, he was still fighting the fascists even in old age. During an attempted coup in 1981, Carrillo refused to hide and take cover when nationalist civil guards fired on the parliament building in Madrid.
He continued to be active in Spanish politics even as an octogenarian, writing essays and hosting a weekly radio program
"I am a politician with a sense of reality," he told Reuters.
"If you can say anything good about me, it's that I have lived many years and actively participated in many episodes of Spain's history.”
El Pais commented that Carrillo was respected across the political spectrum (except for the far-right, presumably) for his efforts to compromise with other parties during Spain’s transition to democracy. He was also praised for refraining from seeking revenge from nationalists.
A 65-year-old Madrid resident named Raúl Dalto, who was the first line to view Carrillo in the chapel, said: “He was a perfect example of political flexibility.”
Laura Gonzalez, assistant professor of finance and business economics at Fordham University in New York, said that the support for the Communist Party has held at about 10 percent of the Spanish electorate over the past fifteen to twenty years.
“[The party] used to have a broader support and more charismatic leaders,” she said.
Sometimes, its representatives do enter government through coalitions.”
Gonzalez commented that, based on press accounts, the Communists reject the Spanish Royal family (by not attending their events) and are strong supporters of “green” movements.
“It is not clear if the [ongoing] austerity measures in Spain will give them more power or not,” she added.
“Most likely it will benefit the Socialists given that [Prime Minister] Rajoy's conservative party is not creating jobs, has neither clear plans, nor a good rapport in the EU.”
Gonzalez also pointed out that while Americans sometimes equate Communists and Socialists, the distinctions between the parties are very sharp in Europe.
“Communists believe in communist regimes, with one rule, and Socialists believe in a democracy with all kinds of parties and a strong public system,” she said. “In general, during the time of the Spanish Civil War, and all the way up to the present, the majority of Spaniards and Europeans are very wary of both extreme right and left movements.”