Seventy-five years ago today, the Nazis ransacked the offices and library of German sex-researcher and gay-rights activist Magnus Hirschfeld, seizing hundreds of books that were burned in a towering pyre four days later.

The Jerusalem Post reports that to mark the day, Berlin dedicated a stretch of the Spree river to Hirschfeld, while the city’s Charite hospital opened a new exhibition of his work called “Sex Burns.”

The tributes to Hirschfeld are “a clear acknowledgment for gays that a persecution has taken place and that reparation is necessary,” said Alexander Zinn, head of Germany’s Lesbian and Gay Association, at the dedication ceremony.

“That is a first step in the right direction,” said Zinn.

Nazi Germany declared homosexuality an aberration that threatened the German race and convicted some 50,000 homosexuals as criminals. An estimated 10,000 to 15,000 homosexuals, mostly men, were deported to concentration camps, where few survived.

About Hirschfeld: 

Hirschfeld was born in 1868, in Kolberg. After attending medical school, he became popular as a physician, sexologist, and gay activist. Around 1900, Hirschfeld developed the theory of a third, “intermediate sex” between men and women. He was interested in the study of a wide variety of sexual and erotic urges, at a time when the early taxonomy of sexual identity labels was still being formed. Hirschfeld was both quoted and caricatured in the press as a vociferous expert on sexual manners, receiving the epithet “the Einstein of Sex”. He saw himself as a campaigner and a scientist, investigating and cataloging many varieties of sexuality, not just homosexuality. He coined the word “transvestism,” for example.

When the Nazis took power they destroyed his Institut and burned down the library on May 6, 1933. The press-library pictures and archival newsreel film of Nazi book-burnings seen today are usually pictures of Hirschfeld’s library ablaze. At the time of the book burning, Hirschfeld was away from Germany on a world speaking tour. Hirschfeld never returned to Germany. He died of a heart attack on his 67th birthday in 1935 in Nice, where he is buried.