Iamblichus' Life of Pythagoras

...and easily, but continually, certain disciplines—which he said he had learned from the BarbariansTo the Greeks, anyone who did not speak Greek was considered a "Barbarian." in his youth—so that he would not be overwhelmed by receiving them all at once, as they were now beginning to slip from his memory due to old age. The young man immediately agreed to the conditions, hoping for the necessary support. Pythagoras therefore endeavored to instruct him in arithmetic and geometry, drawing each of his demonstrations on an abacus (a sand-covered board used for geometric figures) and giving the youth three oboli (small Greek coins) as a reward for every figure he learned. He continued this for a long time, inciting him toward geometric theory through the desire for reward, diligently and in the best order giving him three oboli for every figure he mastered. But when the wise man observed that the elegance, sweetness, and connection of these disciplines, to which the youth had been led in an orderly path, had so captivated him that he would not neglect their pursuit even if he were to suffer extreme poverty, he feigned poverty himself and an inability to give him three oboli any longer. But the youth, on hearing this, replied, “I am able to learn and receive your disciplines without these.” Pythagoras then said, “But I do not have the means to procure sufficient food for myself.” Since it is necessary to labor to obtain daily necessities and mortal food, it would not be proper for his attention to be distracted by the abacus and by “stupid and vain pursuits.” The youth, however, vehemently abhorring the thought of discontinuing his studies, replied: “I will provide for you in the future, and repay your kindness in a way resembling that of the storkReferring to the popular belief that young storks care for their aging parents.: for I, in my turn, will give you three oboli for every figure.” From this time on, he was so captivated by these disciplines that he alone of all the Samians migrated from his country with Pythagoras, sharing the same name with him, though he was the son of Eratocles.