Dionysius of Cyrene (Greek: Διονύσιος ὁ Κυρηναῖος), lived c. 150 BC, was a Stoic philosopher and mathematician.

He was a pupil of Diogenes of Babylon and Antipater of Tarsus.

He was famed as a mathematician, and he is probably the Dionysius whose arguments are attacked by Philodemus in his book On Signs (Latin: De Signis),[1] where Dionysius is reported as arguing that the Sun must be very large because it reappears slowly from behind an obstruction.[2]


  1. ^ Allen, J., Inference from Signs: Ancient Debates about the Nature of Evidence, p. 207. Oxford University Press. (2001).[ISBN missing]
  2. ^ Barnes, J., "Pyrrhonism, Belief and Causation. Observations on the Skepticism of Sextus Empiricus", pp. 2661–2662, in Aufstieg und Niedergang der römischen Welt:: Geschichte und Kultur Roms im Spiegel der neueren Forschung. ed. Werk, Vogt, Haase, Temporini. Walter de Gruyter. (1997).[ISBN missing]