The earliest account of his teaching is given by Philolaus (“Lover of the People,” an auspicious name) of Tarentum, who, born about forty or fifty years after the death of his master--was thus contemporary with Sokrates and Plato. His _Pythagorean System_, in three books, was so highly esteemed by Plato that he is said to have given £400 or £500 for a copy, and to have incorporated the principal part of it in his _Timæus_. Sharing the fate of so many other valuable products of the Greek genius, it has long since perished. Our remaining authorities for the Life are Diogenes of Laerte, Porphyry, one of the most erudite writers of any age, and Iamblichus. Of these, the biography of the last is the fullest, if not the most critical; that of Porphyry wants the beginning and the end; whilst of the ten books of Iamblichus _On the Pythagorean Sect_ (Περὶ Πυθαγόρου Αἱρέσεως), of which only five remain, the first was devoted to the life of the founder. Diogenes, who seems to have been of the school of Epikurus, belongs to the second, while Porphyry and Iamblichus, the well-known exponents of Neo-Platonism, wrote in the third and fourth centuries of our era. Pythagoras was born in the Island of Samos, somewhere about the year 570 B.C. At some period in his youth, Polykrates--celebrated by the fine story of Herodotus--had acquired the _tyranny_ of Samos, and his rule, like that of most of his compeers, has deserved the stigma of the modern meaning of the Greek equivalent for princely and monarchical government. The future philosopher, we are told, unable to descend to the ordinary arts of sycophancy and dissimulation, left his country, and entered, like the Sirian philosopher of Voltaire, upon an extensive course of travels--extensive for the age in which he lived. How far he actually travelled is uncertain. He visited Egypt, the great nurse of the old-world science, and Syria, and it is not impossible that he may have penetrated eastwards as far as Babylon, perhaps as the captive of the recent conqueror of Egypt--the Persian Kambyses. It was in the East, and particularly in Egypt, that he probably imbibed the dogma of the immortality of the soul, or, as he chose to represent it to the public, that of the _metempsychosis_--a fancy widely spread in the eastern theologies.