
Pythagoras (c.530BC), who popularized the theory of transmigration, believed that he had once existed Euphorbus, during the battle of Troy (c.1200BC), and also that he could recognize the voice of a deceased friend in the yelping of a puppy.

Pythagoras (c.530BC), who popularized the theory of transmigration, believed that he had once existed Euphorbus, during the battle of Troy (c.1200BC), and also that he could recognize the voice of a deceased friend in the yelping of a puppy.

In religio-mythology, transmigration refers to the theory, popularized in Greece, supposedly by Pherecydes (c.540BC), and India, derived adopted from ancient Egypt religio-philosophy, that when a person dies their soul "migrates" or is "transmitted" into the body of another human or animal.

Overview
In c.540BC, Pherecydes (c.580-520BC), after studying philosophy in Egypt (Josephus, c.80) (Ѻ) (Cedrenus, c.1050) (Ѻ), therein likely learning their soul theory (see: Egyptian human), purported “invented” the Greek theory of the “soul”, as reported by Cicero (Tusculam Dispulat, c.55BC), as cited by Baron d’Holbach (1770). [1]

In c.530BC, Pythagoras (c.570-490BC), who studied under Pherecydes (Laertius, 230) (Ѻ), and who also studied in Egypt, came to believe in the theory of transmigration of souls and therein seemingly to popularize it in his works. Pythagoras, according to one story (fragment A31), claimed he was able to recall the shield he had used during the battle of Troy (c.1200BC) when he was incarnate as Euphorbus (Ѻ). In another case, Pythagoras, according to Xenophanes (fragment B7), claimed to be able to recognize the voice of a deceased friend in the yelping of the puppy into which his soul had passed. [3]

Quotes
The following are related quotes:

“Cicero said the opinion about the immortality of the soul was first introduced by Pherecydes of Syros in the time of King Tullus (others attribute it to Thales, others to others). It is the part of the human science that is treated with the most reservation and doubt. The firmest dogmatists are forced to take cover in the shadow of the academy. No one knows what Aristotle taught about the subject (or even all of the ancients in general who handle it with unsteady belief) and he left it to his successors to battle it out about his opinion on the matter. It is marvelous how those who are stubborn in this opinion about the immortality of our souls come up short and are powerless to establish it by their human powers. They are the dreams of a man who teaches nothing, but is hopeful. As Cicero said: ‘dreams are not of a teacher, but of the wisher’ (somnia sunt non docentus, sed optantis) (Academia, 2:38).”
— Michel Montaigne (c.1590), Essays (§2:12); cited by Jean Meslier (1729) in The Testament (pg. 570) [2]

“Herodotus upon this occasion says, that the whole romance of the soul and its transmigrations was invented by the Egyptians, and propagated in Greece by men, who pretended to be its authors. I know their names, adds he, but shall not mention them (lib. 2). Cicero, however, has positively informed us, that it was Pherecydes, master of Pythagoras. Tuscul. lib. 1, sect. 16. Now admitting that this system was at that period a novelty, it accounts for Solomon's treating it as a fable, who lived 130 years before Pherecydes.”
— Constantin Volney (1791), The Ruins (Ѻ)

References
1. Holbach, Baron. (1770). The System of Nature: Laws of the Moral and Physical World (notes by Denis Diderot; translator: H.D. Robinson) (pg. 118). J.P. Mendum, 1889.
2. (a) Montaigne, Michel. (c.1590). Essays (§2.12). Publisher.
(b) Meslier, Jean. (1729). Testament: Memoir of the Thoughts and Sentiments of Jean Meslier (translator: Michael Shreve; preface: Michel Onfray) (pg. 570). Prometheus Books.
3. Empedocles. (435BC). The Poem of Empedocles: a Text and Translation with an Introduction (editor: Brad Inwood) (pg. 56). University of Toronto Press, 1992.

External links
● Transmigration of the soul (redirect → reincarnation) – Wikipedia.