In 1925 Grau participated in the Weida Conference, an international meeting of occult leaders at
Hohenleuben, along with his lodge secretary
Eugen Grosche (Frater Gregorius), Master of the Danzig Lodge, Otto Gebhardi (Frater Ich will), Gebhardi's lover Martha Kuntzel (Soror Ich will es), Heinrich Tranker (as Frater Recnartus, head of the Rosicrucian occult lodge Collegium Pansophicum, aka Pansophic Orient Lodge, Berlin) and his wife Helen, and
Aleister Crowley with his entourage of
Leah Hirsig, Dorothy Olsen, and Norman Mudd. Grau shot a film of the conference, currently lost. ==Later years==