In Greek literature they are mentioned in association with the Persian magi, the Chaldaeans of the Assyrians or the Babylonians, the druids of the Celts, and the priests of Egypt, etc. Some sources claim that famous figures such as Lycurgus, Pythagoras and Democritus may have met them. They are mentioned by authors such as Philo, Lucian, Clement of Alexandria, Philostratus, and Heliodorus of Emesa. These reports are thought to have served as models to Cynics as well as Christian ascetics. Many authors have discussed the purported questions by Alexander the Great and answers by the Gymnosophists.