ɐkˈoːɹdɪŋ tə lˈɛdʒənd, ðə mˈɑːnɐstɚɹi wʌz fˈaʊndᵻd ɪnðə twˈɛlfθ sˈɛntʃɚɹi baɪ tˈuː sˈɪstɚz ʌvðɪ ɚɹˌɪstəkɹˈæɾɪk fˈæmɪli ʃlˈɔsbɜːɡ ɪn lˈeɪɾɚ tɹɐdˈɪʃən kˈɔːld ʃlˈuːsɪlbˌɜːɡ, hˌuːz kˈæsəl wʌz nɪɹbˈaɪ, ænd kˈɔːld ɪn tʃˈɛlə dˈeɪ, ɹˈɛndɚɹɪŋ ɡˈɑːts zˈɛl ɪn dʒˈɜːmən.
According to legend, the monastery was founded in the 12th century by two sisters of the aristocratic family Schlossberg (in later tradition called Schlüsselberg), whose castle was nearby, and called in Cella Dei, rendering Gottes Zelle in German.