Manichaism, a gnostic religion founded by the prophet Mani in the 3rd century AD, is a word that refers to a certain set of beliefs and practices. Synonyms for this word include Manicheism, Manichaeism, and Manicheeism. These terms all refer to the same religion and are variations in the spelling of the word. Manichaism is based on the idea of dualism, where there are two opposing forces of good and evil that are constantly battling for power. The religion was popular in the ancient world, and although it declined in popularity, its teachings and influences can still be seen in many different areas of modern society, such as art, literature, and philosophy.