I came across this text by Professor J. Donald Hughes at the University of Denver. He writes about the history of dream interpretation from the earliest times. Here is an excerpt - but see link below if you want to dig into it - so fascinating!
“Dream interpretation was regarded by ancient peoples in Mesopotamia, Egypt, Greece, and Rome as an art requiring intelligence and, sometimes, divine inspiration. It became a motif in literature.
It was treated as a science by philosophers and physicians. Dreams were thought to come either as clear messages, or as symbols requiring interpretation. In a method called incubation, the dreamer could sleep in a sacred place in expectation of a dream that would elucidate a problem for which the dreamer desired guidance.
Dream-books listing images and their meanings were popular. Historians reported leaders' famous dreams that affected the course of events. Very few ancient writers were skeptical of dreams; Cicero was one. Dream interpretation was an honored profession with exponents such as Artemidorus of Daldis. Ancient dream traditions and beliefs can provide perspective for consideration of more recent theories of dream interpretation.”
Excerpt from “A history of Dream Interpretation in Western Civilization from the earliest times through the middle ages” by J. Donald Hughes, Professor of History at University of Denver