In the Aegaean Sea between Miletus and Athens lies a small island called Samos, which during ancient Greece was the main commercial rival of Miletus and also happened to be the birthplace of its leading philosophical rival, Pythagoras (560-480 B.C.E.). Expelled by Polycrates, the tyrant of Samos, he migrated to Crotona, a Dorian colony in southern Italy where he became the leader of a religious brotherhood based on ancient Orphic rites, similar to the Hindu religious tradition, designed to purify the soul so as to free it from the "wheel of birth." His method, however, relied on mathematics and music to achieve enlightenment.

... Pythagoras not only invented new string instruments instruments (some of which became the basis for the guitar) but showed empirically that these ratios hold for vibrating strings as well as for resonating air columns, thereby laying the foundations for the subsequent construction of pipe organs. His followers, sworn to secrecy about his musical, mathematical and philosophical discoveries, swore oaths on the tetractys, a series of dots summarizing the musical harmonies. The Pythagoreans were so impressed by the tetractys that they saw in it the secret insight that all of nature can be understood through mathematics .... The secret oath of his students began:

"By him that gave to our generation the tetractys which contains the fountain and root of eternal nature..."

bio by Daniel Kolak in Lovers of Wisdom
(Wadsworth, 1997)