"Considerable evidence relates the relationships between the sages of Greece and of Egypt. In the 5th century BC, Herodotus visited Egypt and conversed with the priests. In his history he discusses the Osirian mysteries celebrated at Sais. For him, the mys-
teries of Greece owed much to Egypt. Comparing the Greek and Egyptian pantheons, he observed that certain divinities of his country had their origins among the pharoahs.
There existed a strong tradition which claimed that the great sages of ancient Greece
obtained knowledge from their Egyptian teachers. It was claimed that many among them were initiated into the mysteries, thus assuring the transmission of Egyptian learning into the Greek world. Among them Herodotus spoke only of Solon (c. 640-558). In 'Timaeus' and 'Critas' Plato (427-347), who himself had gone to Egypt, and remained there three years, spoke of the discussion Solon had with the Egyptian priests. In "The Republic", he also emphasized the prestige of the Egyptian priests. Furthermore, he mentioned Thoth in the 'Phaedrus'. Isocrates, a contemporary of Plato, made Egypt the source of philosophy and indicated that Pythagoras went there to be instructed...
Diodorus Siculus (80-20) provided the greatest amount of information concerning the
influence of Egypt upon the sages of Greece. He based this partly on what he had gathered in his encounters with the Egyptian priests, and partly upon the 'Aegyptiaca', a work by Hecataeus of Abdera.
Diodorus stated first of all that Orpheus travelled to Egypt and was initiated into the
Osirian mysteries. After returning to his homeland aroud the 6th c. BC, he instituted new rites that were called the Orphic mysteries. Diodorus also stated that rites observed in Eleusis by the Athenians were similar to those of the Egyptians. Plutarch (c. AD 50-125) later remarked that the Orphic and Bacchic mysteries were really of Egyptian and Pythagorean origin. Diodorus also reported on the travels of Solon and of Thales of Miletus (624-548 BC), who visited the priests and measured the pyramids. Plutarch declared that Thales brought Egyptian geometry back to Greece. Diodorus also claimed that Thales urged Pythagorus to go to Egypt, and it was in this country that the latter conceived the concept of the migration of souls. Iamblichus later added that Pythagorus had studied in the Egyptian temples for twenty two years, and, having received this training, he established his own school in Crotona, Italy, and he taught what he had learned in the Egyptian mystery schools. Finally, Diodorus reported that in the 5th century, Democritus (c. 460-370 BC), discoverer of the atom, was taught by the geometers of the pharoah, and then initiated in the Egyptian temples.
...Plutarch, a member of the sacerdotal college of Apollo in Delphi, where he was high priest, also sought knowledge along the banks of the Nile. While there, he was initiated
by Clea, a priestess of Isis and Osiris. In his book 'Isis and Osiris', Plutarch spoke of the
"works called 'Books of Hermes', and emphasized the importance of Egyptian astrology.
He also reported that many authorities declared Isis to be the daughter of Hermes."
"Rosicrucian Histories and Mysteries" - Christian Rebisse