Plotinus was a Greek Platonist philosopher, born and raised in Roman Egypt. Plotinus is regarded by modern scholarship as the founder of Neoplatonism. His teacher was the self-taught philosopher Ammonius Saccas, who belonged to the Platonic tradition. Historians of the 19th century invented the term "neoplatonism" and applied it to refer to Plotinus and his philosophy, which was vastly influential during late antiquity, the Middle Ages, and the Renaissance. Much of the biographical information about Plotinus comes from Porphyry's preface to his edition of Plotinus' most notable literary work, The Enneads. In his metaphysical writings, Plotinus described three fundamental principles: the One, the Intellect, and the Soul. His works have inspired centuries of pagan, Jewish, Christian, Gnostic, and early Islamic metaphysicians and mystics, including developing precepts that influence mainstream theological concepts within religions, such as his work on duality of the One in two metaphysical states.

Eunapius was a Greek sophist, rhetorician, and historian from Sardis in the region of Lydia in Asia Minor. His principal surviving work is the Lives of Philosophers and Sophists, a collection of the biographies of 23 philosophers and sophists. The exact date of his death is unknown but speculated sometime after 414 AD during the reign of Theodosius II.