 One noted commonality among practitioners of necromancy was usually the utilization of certain toxic and hallucinogenic plants from the nightshade family such as black henbane, jimson weed, belladonna or mandrake, usually in magic salves or potions.Medieval necromancy is believed to be a synthesis of astral magic derived from Arabic influences and exorcism derived from Christian and Jewish teachings.Arabic influences are evident in rituals that involve moon phases, sun placement, day and time.