Macrobius (c. 400), Latin writer, who became influential in the European Middle Ages because of his Commentary on the Dream of Scipio (transl. by William Harris Stahl, New York 1952). Cicero's Sonium Scipionis is the closing portion of his De re publica. In his commentary Macrobius distinguishes between five types of dreams:
1. insomnium - nightmare or troubled dream
2. visium - apparition or hallucination
3. somnium - ordinary or enigmatic dream
4. oraculum - oracular or prophetic dream
5. visio - prophetic vision or visionary dream

Nearly all medieval theorists classify dreams in essentially the same way, e.g. John of Salisbury in his Policraticus, and the poets frequently refer to this typology, e.g. Chaucer in his dream-visions.