The Gregorian calendar, also called the Western calendar and the Christian calendar, is internationally the most widely used civil calendar. It is named for Pope Gregory XIII, who refined the Julian calendar.
Many Protestant countries initially objected to adopting a Catholic innovation, the Gregorian calendar. Some Protestants feared the new calendar was part of a plot to return them to the Catholic fold. The last year, when the left out of 10 days was enough to synchronize the Gregorian and Julian calendars was 1700. Those who missed it had to left out 11 days, and 1-1 more with every century passed.
The French Revolution introduced lots of new ideas, some of them lasting in our days. However their calendar reform was not among them. It lasted only for twelve years.
