Events in History Gregory Conquers Julius Caesar Dec 10 France begins use of Gregorian calendarRead Article Pope Gregory XIII with the calendar that was to make his name Read Article Dec 14 Zealand, Brabant Netherlands adopt Gregorian calendar, tomorrow is 12/25 Dec 15 Leidse university names Rembert Dodoens professor of botany and medicine Dec 15 Spanish Netherlands, Denmark and Norway adopt the Gregorian calendar Dec 21 Flanders adopts Gregorian calendar, tomorrow is Jan 1 1583 Dec 25 Zealand and Brabant adopts Gregorian calendar, yesterday was Dec 14th Deaths in History Dec 11 Fernando Alvarez de Toledo, Spanish noble and diplomat (governor of the Netherlands (1567–1573)), dies at about 75 1581 On This Day in History 1583