Thirteen-year-old Charles IX becomes king of France, with Queen Mother Catherine de' Medici as regent.

Charles IX was King of France from 1560 until his death in 1574. He ascended the French throne upon the death of his brother Francis II in 1560, and as such was the penultimate monarch of the House of Valois.

Catherine de' Medici was an Italian Florentine noblewoman of the Medici family and Queen of France from 1547 to 1559 by marriage to King Henry II. She was the mother of French kings Francis II, Charles IX, and Henry III. She was a cousin of Pope Clement VII. The years during which her sons reigned have been called "the age of Catherine de' Medici" since she had extensive, albeit at times varying, influence on the political life of France.

December 5 is the 339th day of the year in the Gregorian calendar; 26 days remain until the end of the year.