For our theme, it is irrelevant whether Pythagoras and others were actually in Egypt. What is important is the nimbus with which they could be surrounded through their supposed contact with Egypt and the wisdom of its priests. Iamblichus affirms that Thales sent Pythagoras to Egypt, for Thales himself had derived everything for which he was considered a sage from his association with the priests of Memphis and Thebes. The theme that all wisdom sprang originally from Egypt became ever more tightly woven into the legends.
“Foreign Wonderland on the Nile”, The Secret Lore of Egypt: Its Impact on the West, by Erik Hornung