Claudio Pavone, who has died aged 95, was the leading historian of the Italian resistance during the second world war. His fame was largely due to his monumental work Una Guerra Civile: Saggio Storico sulla Moralità nella Resistenza (1991), translated into English as A Civil War: A History of the Italian Resistance (2013).

Using the term “civil war” to characterise the Italian resistance acknowledged that the traditional depiction within Italy of the conflict as one of national liberation of all Italians against the Nazis and their fascist allies was reductive and one-sided. Perhaps only a historian such as Pavone, with unmistakably anti-fascist credentials, could remind Italians that many of their countrymen, even in the final years of the war, had been genuine fascists, ready to die for Benito Mussolini, the leader they knew as Il Duce, and his “social republic”.

Born in Rome, two years before the appointment of Mussolini as prime minister, Pavone grew up in a prosperous middle-class family; his father was a lawyer who worked for the Confindustria, the employers’ association. Early in 1943, Pavone graduated in law from the University of Rome and was immediately drafted. However, that April he was granted extended leave because of the sudden death of his father.

The following months were crucial ones in Italian history: on 25 July Mussolini was arrested by King Victor Emmanuel, only to be liberated soon after by the Germans and thus able to rally his troops in northern Italy to continue the fight against the allies. As for the king, having signed an armistice on 3 September with the Anglo-American forces under General Dwight Eisenhower (effectively switching sides), he was able to escape to the south on 8 September – an ignominious flight that left the Italian people and army in disarray.

Pavone, then only 22, was one of the many young Italians who, having witnessed the crumbling of a spineless and corrupt ruling class, decided to join the resistance. On 22 October, he was distributing anti-fascist material in the streets of Rome when, realising that the curfew was imminent, in a panic he threw the leaflets into a large car parked nearby, and ran away. As he recalled in his memoirs, he had chosen the “wrong” car, since that one belonged, of all people, to the head of the fascist secret police. Pavone was quickly arrested and jailed.

Freed on 20 August 1944, he continued to work on behalf of the resistance in Milan. After the war Pavone, although a sympathiser of the moderate left, eschewed active politics to work as an archivist in the state archives. Only in 1975, when he was in his 50s, did he achieve an academic position, as a history professor at the University of Pisa.

Many of his earlier scattered essays, written when he was an archivist, were collected in 1995 in a volume called La Continuità dello Stato, which dealt with the issue of continuity between the fascist regime and democratic Italy, both in terms of institutions and personnel. This is something that must have particularly struck him since Guido Leto, the head of the fascist secret police who had arrested him in 1943, continued to be gainfully employed by the secret services even in post-fascist Italy.

Pavone’s fame rests almost entirely on A Civil War: A History of the Italian Resistance. As is often the case, the title dominated the reception of the book, so that many who had not read it registered their disapproval, believing that Pavone, by adopting such a title, had capitulated before neofascist historical revisionism attributing to both sides (fascists and anti-fascists) equal dignity. The title (though an excellent marketing tool) was unfortunate (as the British historian of the Italian resistance Philip Cooke has pointed out), since the book offered a more complex, nuanced vision.

According to Pavone there were three aspects to the resistance. It was certainly a patriotic war of national liberation fought by those who wanted to free the country from German occupation; but it was also a class war fought mainly but not exclusively by communists, who looked forward to a socialist society; and finally, it was also a civil war between partisans (monarchists, communists, liberals and socialists) and the fascists who had rallied round Mussolini. Many objected, preferring to see the fascists as simply tools of the Nazis, but eventually most of the scholarship came round to Pavone, even though some on the right tried to exploit the debate to denigrate the partisans.

Pavone also distinguished between the military resistance of the few partisans, and a wider resistance of hearts and minds, which involved all those who supported anti-fascism and looked forward to a democratic Italy. For them, the resistance was a great moral quest, a way of redeeming Italy from the stigma of having allowed the establishment of fascism. This moral and psychological dimension enabled a whole people, not just the few who actively resisted, to claim that they were not passive objects of history, first enslaved by the Nazis and fascists then liberated by others, but that they deserved their freedom because they had fought for it.

Pavone is survived by his second wife, the historian Anna Rossi Doria, and three daughters, Liberiana, Flaminia and Sabina, from his first marriage, which ended in divorce.

• Claudio Pavone, historian, born 30 November 1920; died 29 November 2016