English summary: Peter Schafer discusses the repercussions of the emerging Christianity on contemporary rabbinic Judaism. The idea of a divine duality (Father and Son) or trinity (Father, Son, and Holy Spirit) in particular has left more noticeable traces in rabbinic sources than most scholars admit. The Son of Man from the book of Daniel and the highest angel called Metatron (who even assumes the epithet Lesser God) play an important role. Even the concept of the Messiah's vicarious suffering finds its way back into Judaism - although it had been usurped for centuries by Christian theology....