he was particularly interested in comparative mythology, which in his later works extended beyond the Greek and Roman sources. So we find, for instance, in this study on the nightmare that Roscher turns to Byzantine works, psychological studies of his day on sleep and dreams
This passage traces Roscher’s comparative mythology as a disciplinary practice that deliberately expanded from classical antiquity into Byzantine, Northern European, and Asian sources, establishing the scholarly genealogy behind archetypal psychology’s use of cross-cultural mythic data.
, Pan and the Nightmare, 1972thesis