December 14

John of the Cross, the Spanish mystic and poet of 'The Dark Night of the Soul,' died at Úbeda.

B.K.S. Iyengar, who systematized a precise, alignment-focused method of haṭha yoga and carried it worldwide, was born in Bellur, Karnataka.

Tycho Brahe, whose meticulous pre-telescopic observations of the planets later enabled Kepler's laws of planetary motion, was born in Scania, then under the Danish crown.

Max Planck read his derivation of the blackbody radiation law to the German Physical Society in Berlin, introducing energy quanta and the constant now bearing his name, an event widely marked as the birth of quantum theory.