Dream incubation refers to the practice of seeking dreams for specific purposes-healing, financial guidance, general advice, divination, and so on. Dream incubation was extremely popular in the ancient world, and was a major phenomenon in societies as diverse as ancient Mesopotamia, Egypt, Greece, and Rome. The theoretical structure underlying this practice in all ancient civilizations has been outlined by Scott Cunningham as follows:
1. The divinities are concerned about Their worshippers.
2. Dreams can be sent by goddesses and gods.
3. The nearest that a worshipper can be to a deity, while in a corporeal state, is within the confines of Her or His temple.
4. Thus, sleeping within the temple will be the most effective method of producing a divine dream.
The practice of dream incubation in the temples of the ancient world may have developed independently in Mesopotamia and Egypt, or the practice may have emerged in one of these societies and later been transmitted to the other. The seeming obsession of Mesopotamians with divination suggests Mesopotamia as the ultimate source of this practice, indicating that the first systematic use of dream incubation was for the purpose of gaining knowledge of the future. This contrasts with the Hellenistic period, in which the primary purpose of dream incubation was for healing, principally at temples dedicated to Aesculapius. The practice continued into the Christian era, with reports of worshipers seeking healing in dreams at Catholic pilgrimage sites (particularly at churches built over the remains of Aesculapius's temples) as late as the early twentieth century.
The earliest temples to observe this practice were not dedicated solely to the task of guiding worshipers in their dreamwork, but the basic pattern was much the same. People went to temples to "camp out" and sleep with the intention of receiving a dream from the gods that would provide healing or an answer to a vexing question. The dreamer fasted and engaged in other rituals before lying down to sleep. In cases where the temple was too far away from the person seeking dream guidance, or when the person was too sick to undertake the required fasts, baths, or other rituals, another person could act as a surrogate for the seeker. During the period of Babylonian ascendancy in ancient Mesopotamia, the practice was to have a professional dreamer-priest seek the answer to one's question. During other periods when the seeker personally sought dream guidance, priests were often available to help interpret the dreams.
