Pythagoras (Gr.). The most famous of mystic philosophers, born at Samos, about 586 b.c. He seems to have travelled all over the world, and to have culled his philosophy from the various systems to which he had access. Thus, he studied the esoteric sciences with the Brachmanes of India, and astronomy and astrology in Chaldea and Egypt. He is known to this day in the former country under the name of Yavanâchârya (“Ionian teacher”). After returning he settled in Crotona, in Magna Grecia, where he established a college to which very soon resorted all the best intellects of the civilised centres. His father was one Mnesarchus of Samos, and was a man of noble birth and learning. It was Pythagoras. who was the first to teach the heliocentric system, and who was the greatest proficient in geometry of his century. It was he also who created the word “philosopher,” composed of two words meaning a “lover of wisdom”—philo-sophos. As the greatest mathematician, geometer and astronomer of historical antiquity, and also the highest of the metaphysicians and scholars, Pythagoras has won imperishable fame. He taught reincarnation as it is professed in India and much else of the Secret Wisdom.

— H. P. Blavatsky, Theosophical Glossary

Key Texts

It is said that Pythagoras authored at least one work, titled “The Sacred Discourse” (‘Ιερὸς λὀγος); Diogenes Laertius lists three works by Pythagoras (“one on education, one on politics, and one Natural Philosophy”) and Iamblichus indicates that he also authored concise “commentaries,” but unfortunately all these are no longer extant. However, many of Pythagoras’s teachings have survived through his followers and among later philosophers.

“. . . it is said, that he [Pythagoras] was the author of a compound divine philosophy and worship of the Gods; having learnt indeed some things from the followers of Orpheus, but others from the Egyptian priests; some from the Chaldæans and Magi; some from the mysteries performed in Eleusis, in Imbrus, Samothracia, and Delos; and some also from those which are performed by the Celtæ, and in Iberia. It is also said that the Sacred Discourse of Pythagoras is extant among the Latins, and is read not to all, nor by all of them, but by those who are promptly disposed to learn what is excellent, and apply themselves to nothing base.”—Iamblichus, Life of Pythagoras

Of his wisdom, however, the commentaries written by the Pythagoreans afford, in short, the greatest indication; for they adhere to truth in every thing, and are more concise than all other compositions, so that they savour of the ancient elegance of style, and the conclusions are exquisitely deduced with divine science. They are also replete with the most condensed conceptions, and are in other respects various and diversified both in the form and the matter. At one and the same time likewise, they are transcendently excellent, and without any deficiency in the diction, and are in an eminent degree full of clear and indubitable arguments, accompanied with scientific demonstration, and as it is said, the most perfect syllogism; as he will find to be the case, who, proceeding in such paths as are fit, does not negligently peruse them. This science, therefore, concerning intelligible natures and the Gods, Pythagoras delivers in his writings from a supernal origin. Afterwards, he teaches the whole of physics, and unfolds completely ethical philosophy and logic. He likewise delivers all-various disciplines, and the most excellent sciences. And in short there is nothing pertaining to human knowledge which is not accurately discussed in these writings. If therefore it is acknowledged, that of the [Pythagoric] writings which are now in circulation, some were written by Pythagoras himself, but others consist of what he was heard to say, and on this account are anonymous, but are referred to Pythagoras as their author;—if this be the case, it is evident that he was abundantly skilled in all wisdom.”—Iamblichus, Life of Pythagoras

Now they say that Pythagoras did not leave behind him a single book; but they talk foolishly; for Heraclitus, the natural philosopher, speaks plainly enough of him, saying, “Pythagoras, the son of Mnesarchus, was the most learned of all men in history and having, selected from these writings, he thus formed his own wisdom and extensive learning, and mischievous art.” Thus he speaks, because Pythagoras, in the beginning of his treatise on natural philosophy, writes in the following manner: “By the air which I breathe, and by the water which I drink, I will not endure to be blamed on account of this discourse.”

There are three volumes extant written by Pythagoras: one on education, one on politics, and one Natural Philosophy. The treatise which is now extant under the name of Pythagoras is the work of [Lysis], of Tarentum, a philosopher of the Pythagorean school, who fled to Thebes, and became the teacher of Epaminondas. Heraclides, the son of Sarapion, in his Abridgment of [N]otion says that he wrote a poem in epic verse upon the Universe; and besides that a sacred poem which begins thus:

“Dear youths, I warn you cherish peace divine, And in your hearts lay deep these words of mine.”

A third about the Soul; a fourth on Piety; a fifth entitled Helothales, which was the name of the father of Epicharmus of Cos; a sixth, called Crotona; and other poems too. But the mystic discourse which is extant under his name, they say is really the work of Hippasus, having been composed with a view to bring Pythagoras into disrepute. There were also many other books composed by Aston of Crotona, and attributed to Pythagoras. Aristoxenus asserts that Pythagoras derived the greater part of his ethical doctrines from Themistoclea, the priestess at Delphi. Ion of Chios, in his Victories, says that he wrote some poems and attributed them to Orpheus. His also, it is said, is the poem called Scopadaea, which begins thus; “Behave not shamelessly to any one.”—Diogenes Laertius, Life of Pythagoras

Iamblichus’ Life of Pythagoras
The Golden Verses of Pythagoras
Fragments of the Ethical Writings of Certain Pythagoreans
Pythagoric Sentences, Similitudes, Symbols, etc. (see below for translations)


Selected Articles, Commentaries, etc.

See also:

Pythagoras: His Life and Teaching, a Compendium of Classical Sources, by Thomas Stanley (1687)
Lore and Science in Ancient Pythagoreanism, by Walter Burkert (1972)
The Pythagorean Sourcebook and Library: An Anthology of Ancient Writings Which Relate to Pythagoras and Pythagorean Philosophy, by David R. Fideler (1987)
Pythagoras and the Early Pythagoreans, by Leonid Zhmud (2012)
Pythagoras and the Pythagoreans: A Brief History, by Charles H. Kahn (2001)
Pythagoras: His Life, Teaching, and Influence, by Christoph Riedweg (2005)
Plato and Pythagoreanism, by Phillip Sidney Horky (2013)
Measuring Heaven: Pythagoras and his Influence on Thought and Art in Antiquity and the Middle Ages, Christiane Joost-Gaugier (2007)