(Φειδιππίδης), a courier, was sent by the Athenians to Sparta in B. C. 490, to ask for aid against the Persians, and arrived there on the second day from his leaving Athens. The Spartans declared that they were willing to give the required help, but unable to do so immediately, as religious scruples prevented their marching from home before the full moon (see Dict. of Ant. s. v. Carneia). On the return of Pheidippides to Athens, he related that, on his way to Sparta, he had fallen in with Pan, on Mount Parthenium, near Tegea, and that the god had bid him ask the Athenians why they paid him no worship, though he had been hitherto their friend, and ever would be so. In consequence of this revelation, they dedicated a temple to Pan, after the battle of Marathon, and honoured him thenceforth with annual sacrifices and a torch-race (Hdt. 5.105, 106 ; Paus. 1.28, 8.54; Corn. Nep. Milt. 4; Dict. of Ant. s. v. Lampadephoria). In Pausanias and Cornelius Nepos the form of the name is Philippides, which we also find as a various reading in Herodotus.