Giovanni de' Medici, the man who became Leo X, was born. His father had him made cardinal at the youthful age of thirteen. His life was eventful, including time spent as a prisoner of war. As pope, he was known as a patron of art and science. It was to repair St. Peter's Cathedral that he had an indulgence preached. When Luther opposed this, the Reformation was born. Leo has been described as more a prince than a pope. His secular tastes and inability to see the need of reform proved costly to church unity.
Birth of Joseph Mohr, German Roman Catholic priest, in Salzberg, Austria. He was ordained in 1815, and served as assistant priest at St. Nicholas Church in Oberndorf, Austria, from 1817-19. He later became vicar at Hintersee (1828-37), then vicar at Wagrein (1837-48), where he remained until his death in 1848. While at Oberndorf, father Mohr penned the words to a beloved Christmas carol which was set to music by the village schoolmaster and church organist, Franz Gruber. The hymn was finished in time for Christmas Eve mass, December 24, 1818, when "Stille Nacht" ("Silent Night") was sung for the first time. He left nothing behind at his death but a robe, guitar, pipe and pipe bag.