Les Mouvements de Réforme du Calendrier à Travers l'Histoire

Introduction

The Gregorian Calendar is the world's de facto standard, but it has rarely been loved. Its months vary in length from 28 to 31 days, quarters are unequal, and no year begins on the same day of the week. Calendar reformers have periodically proposed sweeping alternatives — some briefly implemented, most ultimately abandoned.

The French Republican Calendar

The most radical calendar reform ever actually implemented was the French Republican Calendar, adopted by the French National Convention in 1793. It divided the year into twelve months of thirty days each, with each month subdivided into three ten-day weeks (décades). The five or six leftover days were grouped into a festival period (sans-culottides) at the year's end. Month names evoked natural phenomena: Vendémiaire (vintage), Brumaire (mist), Nivôse (snow), Thermidor (heat). The Republican Calendar abolished the Christian Sunday, replaced it with the décadi rest day, and reset the year count to Year I from the foundation of the Republic (22 September 1792 Gregorian Calendar). Napoleon abolished it on 1 January 1806, returning France to the Gregorian system.

The Soviet Calendar

The Soviet Union experimented with a five-day week (1929-1931) and then a six-day week (1931-1940), both intended to eliminate the seven-day Christian week and its Sunday rest. The experiments failed to achieve the productivity gains promised and were abandoned in favor of the standard seven-day week.

The World Calendar Proposal

The World Calendar, promoted by the World Calendar Association from the 1930s through the 1950s, proposed a 364-day year divided into four equal quarters of 91 days each (13 weeks of 7 days). One extra day per year (two in leap years) would fall outside the week-day system, labeled 'Worldsday.' This would make every date fall on the same day of the week every year — Christmas would always be Sunday, for instance. The proposal reached the United Nations in 1954 but was rejected, partly due to religious objections to a floating 'blank day' that disrupted the continuous seven-day week.

The International Fixed Calendar

The International Fixed Calendar (also called the Cotsworth calendar) proposed 13 months of exactly 28 days each, with a 13th month named Sol inserted between June and July, plus one or two 'Year Day' blanks. The Eastman Kodak Company used an internal version of this calendar from 1928 to 1989. Proponents argued that equal months simplify business accounting and payroll.

Hanke-Henry Permanent Calendar

In 2004, economists Steve Hanke and Richard Henry proposed the Hanke-Henry Permanent Calendar, which fixes every date to the same day of the week forever by using a 364-day year with an extra week inserted every five or six years. This 'leap week' replaces the leap day, keeping the calendar synchronized with the solar year while eliminating the annual shuffle of weekdays.

Why Reform Fails

Every radical calendar reform faces the same obstacles: religious communities that rely on an unbroken weekly cycle, existing software and legal systems designed around the current calendar, and the sheer inertia of a global standard used by billions of people. The Gregorian Calendar, despite its irregularities, is embedded in global commerce, law, and culture too deeply to dislodge.

Conclusion

Calendar reform movements reveal what each era valued most — rationality, productivity, religious continuity, or astronomical precision. Their consistent failure tells us something equally important: the calendar is not merely a tool but a shared cultural artifact that resists purely rational redesign.

Site	Domain	Focus
UnitFYI	unitfyi.com	Unit conversion for 220 units across 20 categories
TimeFYI	timefyi.com	World clock, timezone converter, sunrise & sunset times
HolidayFYI	holidayfyi.com	Public holidays & observances for 200+ countries
NameFYI	namefyi.com	Name origins, romanization, and cultural naming traditions