After Mussolini’s corpse was hung up on meat hooks on April 29, 1945, in Piazzale Loreto in Milan, where citizens vented their fury at their former leader, he was buried in an unmarked grave in a nearby cemetery. A year later, neo-Fascist loyalists dug up his body and hid it in a convent in Lombardy until 1957, when the remains were returned to Mussolini’s widow, who buried them in the family crypt in Predappio.

In fact, Italian authorities’ efforts to hide the burial site backfired on them, as its location rapidly became a matter of intense interest. “The vitality of Mussolini’s afterworld life was great as long as the mausoleum didn’t exist. A corpse that is nowhere is everywhere,” said Sergio Luzzatto, a historian at the University of Turin who wrote “The Body of Il Duce,” about the corpse’s vicissitudes. The documentary “Il Corpo del Duce,” inspired by the book, will be shown at the Turin Film Festival this month.

“Italians lived the absence of the body as a presence, so continuing the love story between Italians and their leader, which was very carnal in many ways,” Mr. Luzzatto said. That story ended when the body was returned to the family and “it became fixed and sepulchral,” primarily in the guest books at the tomb, where visitors can sign and leave comments.

Those books are now archived in a room on the top floor of the House of Memories, the museum of Duce memorabilia opened in 2001 by Domenico Morosini, a successful Lombardy businessman, in what was once a Mussolini summer home. The registers are shelved under a beam inscribed with what Mr. Morosini said was a Mussolini citation: “It is not impossible to govern Italians, merely useless.”

The museum gets between 2,000 and 3,000 people a year and might attract more, but Mr. Morosini has found it hard to advertise. Road signs to the museum “constantly get knocked down by left-wingers,” he said.