Iamblichus' Life of Pythagoras

...he might receive some impediment in his studies, which engrossed the whole of his attention, he departed privately by night with one Hermodamas (whose surname was Creophilus, and who was the grandson of him who had formerly been the host, friend, and teacher of Homer the poet) to Pherecydes, to Anaximander the natural philosopher, and to Thales at Miletus. He associated with each of these philosophers in such a way that they all loved him, admired his natural endowments, and shared their doctrines with him.

After Thales had gladly admitted him to his intimate confidence, he admired the great difference between him and other young men, whom Pythagoras left far behind in every accomplishment. Thales increased the reputation Pythagoras had already acquired by communicating such disciplines as he was able to impart. Apologizing for his own old age and physical weakness, he exhorted him to sail into Egypt and associate with the Memphian and Diospolitani.e., the priests of Jupiter. priests. For Thales confessed that his own reputation for wisdom was derived from the instructions of these priests, but that he was neither naturally nor by exercise endowed with those excellent prerogatives which were so visibly displayed in Pythagoras. Thales, therefore, gladly announced that he would become the wisest and most divine of all men if he associated with these Egyptian priests.

CHAP. III.

Pythagoras, therefore, having been benefited by Thales in other respects—and especially having learned from him how to be sparing of his time—for the sake of this...