Pherecȳdes in Harpers Dictionary of Classical Antiquities (1898)
A Greek philosopher, of the isle of Syros, about B.C. 600-550; said to have been the first writer of prose. He wrote in the Ionic dialect of the origin of the world and the gods (Cosmogonia and Theogonia). The poetic element seems to have held a predominant place in his prose. He is also said to have been the first to maintain the doctrine of the transmigration of souls, which his pupil Pythagoras borrowed from him.
Pherecydes of Leros in Wikipedia
Pherecydes of Leros (c. 450s BC) was a Greek mythographer and logographer. He came from the island of Leros. Pherecydes spent the greater part of his working life in Athens, and so he was also called Pherecydes of Athens: the encyclopedic Byzantine Suda consider Pherecydes of Athens and of Leros separately.
Pherecydes of Leros should not be confused with Pherecydes of Syros, the mid-6th century philosopher, who was one of the Seven Sages of Greece and was reputed to have been the teacher of Pythagoras.
Pherecydes's great treatises (a history of his native isle, Leros; an essay, On Iphigeneia; and On the Festivals of Dionysus) are all lost. However, numerous fragments of his ten-book genealogies of the gods and heroes, which was written in the Ionian dialect to glorify the ancestors in the heroic age of his 5th century patrons, have been preserved. Pherecydes modified the legends, not in order to rationalize them, but rather to adjust them to popular beliefs. Therefore, Pherecydes cannot be classed with the earlier mythographer Hecataeus of Miletus, whose Genealogiai ("Genealogies") were more skeptical and critical.
Pherecydes was the main source for the mythological encyclopedia, the Bibliotheke mistakenly connected with the name of Apollodorus.