There is a tendency in historical scholarship to confuse the Mani's Living Gospel with another of his works,[4] known as Ertenk or Ardhang/Arzhang (ancient Persian: artha-thanha ≈ "message of truth") or The Picture Book. The Ardhang was in fact a picture-book,[5] given the name of Eikōn in Greek and Coptic. This was a book containing illustrations to accompany and facilitate the understanding of Mani’s cosmology.