- 580/570-c.500 B.C.E. Pythagoras: A Pre-Socratic philosopher. Founder of a major school of philosophy/religion that emphasized the mystical interconnections in numbers, nature, and the human soul. The natural and the ethical world were inseparable.
- 515-c.450 B.C.E. Parmenides: On Nature, extant in fragments. Another of the Pre-Socratic. Extends Pythagoras by insisting that all that exists is unchanging and unified. Therefore, if something is changing, it is illusory. This paves the way for the two-world view important for much mysticism. Influences: Pythagoras.
- 428-348 B.C.E. Plato: Sophist, Republic, Parmenides, many others. Most important of ancient philosophers. His philosophical system provides the basis of most later mystical forms.Influences: Pythagoras, Parmenides.
- 384-322 B.C.EAristotle .: Metaphysics, De Anima, Nicomachean Ethics. While Aristotle himself is not really considered to be a mystic, he is an important influence on later mystics, especially when combined with Plato by Plotinus, and also when Christianized in the high Middle Ages.
- 20 B.C.E.-c.41 C.E.Philo : The Contemplative Life. An Alexandrian Jew who drew from Platonist tradition, Stoicism, and neo-Pythagoreanism to create a fusion of the active or virtuous life and the contemplative life.
- 205-270 C.E.Plotinus : Enneads. The non-Christian, neo-Platonic basis for much Christian, Jewish, and Islamic mysticism. Influences: Plato, Aristotle.
- 232-304 C.E. Porphyry: Isagoge. Compiled Plotinus’ Enneads, and wrote a life of Plotinus. He was strongly anti-Christian, yet he became important in the history of Christian mysticism.
- 411-485 C.E. Proclusor Proclusthe Lycian : Neoplatonic philosopher was born. The Elements of Theology. Athenian Neo-platonist, who influenced Pseudo-Dionysius, and beyond him most of the mystical tradition.