The man behind the triangle theorem ran a secret society that worshipped numbers

Pythagoras founded a religious brotherhood in southern Italy that treated whole numbers as the literal building blocks of reality and believed in metempsychosis — the transmigration of souls between bodies, including animals. Members reportedly swore secrecy and avoided eating beans, and almost nothing he actually said survives outside legend.

— Wikipedia contributors, drawing on Diogenes Laërtius and Porphyry, Pythagoras — c. 570 – c. 495 BC