Like other ancient peoples, the Greeks and Romans placed great importance on the meaning of dreams and visions. They believed that dreams provided a direct connection to their gods and heroes*. They also believed that these gods and heroes might appear in the dreams to provide advice or help in times of need and crisis.
The Greeks and Romans had several categories for dreams. Some dreams did not signify anything important but were just memories of what happened during the day. Other dreams predicted the future. Some dreams were so complex they needed interpretation to be understood. Apollo supposedly gave certain individuals, called seers, the power to interpret dreams. There were even some books that listed the meanings of common dreams. Finally, some dreams provided help or advice from the gods. To receive these dreams, a person was advised to sleep in a sacred spot dedicated to the god from whom he or she needed help. For example, at a shrine in the Greek city of Epidaurus, sick people would sleep in a special room. They hoped that, in their dreams, they would be visited by the healing god Asclepius, who would tell them how to cure their illnesses.
* hero in mythology, a person of great strength or ability, often descended from a god
Ancient writings contain numerous descriptions of dreams and their interpretations. According to the Greek poet Homer, it was through dreams that Zeus revealed his will. The emperor Constantine I had visions of Christian symbols, which allegedly prompted him to favor Christianity.
Philosophers* argued over the origin of dreams. Some thought that dreams were the result of the brain failing to work properly, while others, such as Plato, believed that dreams came from the gods and, therefore, could be trusted. (See also Cults; Oracles.)
* philosopher scholar or thinker concerned with the study of ideas, including science