Pollak’s Arm, by the German historian Hans von Trotha, tells the story of Ludwig Pollak, a Czech collector and archaeologist who lived in Rome during the first half of the 20th century. Because they were Jewish, Pollak and his family were seized by the Nazis, sent to Auschwitz in October 1943 and murdered. Published in German last year and recently translated into English, Pollak’s Arm is based on real diaries and letters, but it’s a novel that imagines how Pollak saw his life. It confronts a perennial question that pertains to all collectors, fictional or real: are they slightly mad? In Bruce Chatwin’s novel Utz (1988), for example, a porcelain collector has the chance to flee communist Czechoslovakia but doesn’t because he’d have to leave his collection behind. In real life, Pollak and his family received an offer of protection from the Vatican before the Nazis arrested them, but ignored it. Why?

Early in the century, Pollak was a curator at the Museo Barracco, one of the smallest antiquities museums in Rome. It’s located on the Corso Vittorio, between Piazza Navona and Campo de Fiori, an area that swarms with tourists. While the Corso blazes with traffic, the Barracco is almost always empty. It’s a small gem of a museum. There are photos of Pollak’s apartment and collections, and the odd statuette bearing his name as donor. But none of this gives much sense of the man. Von Trotha reminds us that Pollak never actually knew this version of the Barracco, since the building he worked in was torn down by Mussolini to build the Corso Vittorio in the first place.

Pollak is a relatively obscure figure. While rich art collectors are often self-promoters, antiquarian connoisseurs tend to hide. They lie low at auctions, never bidding high for what they really want, though they’re often well connected. Pollak had dealings with Freud, J P Morgan, the Berlin curator Wilhelm von