The following is from a 1901 book by English historian and translator George Mead on a well-known 1st c. philosopher and reformist Apollonius of Tyana, who was of Greek heritage in Roman-controlled Cappadocia, Asia Minor (note the word “Cappadocia” is Iranian in origin given Iranians, Anatolians, Armenians, and Greeks lived in that region for thousands of years prior to the arrival of the Romans):

“And even if we cannot go so far as to entertain the possibility of direct personal contact, there has to be taken into consideration the fact that Pherecydes, the master of Pythagoras, may have been acquainted with some of the main ideas of Vaidic lore.  Pherecydes taught at Ephesus, but was himself most probably a Persian, and it is quite credible that a learned Asiatic, teaching a mystic philosophy and basing his doctrine upon the idea of rebirth, may have had some indirect, if not direct, knowledge of Indo-Aryan thought.”

~ Indo-Aryans refer to sister culture Vedic Sanskrit to Avestan-Aryans or Iranians… the separation of the Indo-Iranians may have been around 1800 BCE…

[pic source iranicaonline: for educational purposes only]