 Several manuscripts of her works were produced during her lifetime, including the illustrated Rupertsberg manuscript of her first major work, "Scivias" (lost since 1945); the Dendermonde Codex, which contains one version of her musical works; and the Ghent manuscript, which was the first fair-copy made for editing of her final theological work, the "Liber Divinorum Operum".At the end of her life, and probably under her initial guidance, all of her works were edited and gathered into the single Riesenkodex manuscript.Hildegard's most significant works were her three volumes of visionary theology