Ernst Gräfenberg developed in the late 1920s a silver intrauterine device with silk thread that achieved significant contraceptive efficacy rates. He published his results in 1930, but official German gynecology rejected his method — partly for ideological reasons — and his work was suppressed. He fled the Nazis in 1940. Decades later, the copper IUD would take up exactly his principle, without his name receiving due credit in standard clinical practice.