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Gregorian Calendar

All of the Political Graveyard date pages, from January 1, 1701,to December 31, 2050, are dates of the Gregorian calendar.However, other calendars were in use for portions of this era,and the alternate dates are listed.

The Gregorian calendar, now in use almost throughout the world,was introduced by Pope Gregory XIII in 1582 as a reform of thepre-existing Julian calendar.

Under both the Julian and Gregorian calendars, a normal orcommon year has 365 days. Every year divisible by four is a"leap year", with an extra day added to February, for a totalof 366 days. Across each four-year period, the average yearis 365.25 days long.

The trouble was that, to coordinate the calendar year with theposition of the sun — that is, with the seasons —the average year needed to be 11 minutes shorter.

Pope Gregory's solution was to eliminate three leap years outof each 400. Years divisible by 100, but not by 400, such as1700, 1800, and 1900, are not leap years under the Gregoriancalendar.

Different countries and regions switched to the new calendarat different times. France and Spain did so in the 1500s, sotheir New World colonies had the Gregorian calendar from thebeginning. The British Empire and its colonies kept theJulian calendar until 1752. Russia, Greece, and otherOrthodox Christian nations didn't adopt the Gregorian calendaruntil the early 1900s.

Changing from the "old" (Julian) to the "new" (Gregorian)calendar required skipping a number of days: 10 days if thechange was made in the 1500s or 1600s, 11 days in the 1700s,12 days in the 1800s, and 13 days in the 1900s.

In the English-speaking (British) world, the last Julian day,Wednesday, September 2, 1752, was immediately followed by thefirst Gregorian day, Thursday, September 14, 1752.

That was not the only change. Starting with January 1, 1752,they also changed when each yearstarted.

Under the English Julian calendar, the beginning of the yearwas March 25. That meant the last seven days of March wouldbe in a different year than the first part. For example, thelast day of 1731 was March 24, 1731, immediately followed bythe first day of 1732: March 25, 1732.

The confusion was intensified when Scotland, in 1600, changedits year to January 1st through December 31. So for 12 weeksevery year, for more than a century and a half, Scotland was ayear ahead of England.

During that period, in an effort to avoid ambiguity, Englishdates from January 1st to March 24th were customarily written withboth years, such as "February 11, 1731/32".

Alaska

Alaska was part of Russia from 1784 to 1867. Russia (andhence Alaska) was on the Julian calendar during that time.Alaska was also on Russia's side of the International DateLine. That is, in the middle of the day, the date inSitka, Alaska, was the same as the date in St. Petersburg.

When Alaska was sold to the United States in 1867, it crossedthe International Date Lineand switched to theGregorian calendar. So, in Alaska, Friday, October 6, 1867,was immediately followed by Friday, Ocober 18, 1867.

Political Graveyard date pages during 1784-1867 show the datein Russian Alaska, but using English names for days and months.

French Republican Calendar

Following the overthrow of the monarchy in France, therevolutionaries desired to rid the country of the trappingsof religion and the old regime. The metric system of weightsand measures was invented at this time, based on simple,rational multiples of ten.

To replace the Gregorian calendar, a new calendar was alsocreated, with uniform 30-day months, 10-day weeks, 10-hourdays, and 100-minute hours. The years were numbered withRoman numerals.

Most fascinating of all, to replace the Catholic saints'days, each individual day of the year had a different name.It was called the Rural Calendar, as the names were drawnfrom rural life, so representing farm tools, crops, herbs,trees, animals, and minerals.

This new calendar was used in France, and in French coloniesaround the world for about 12 years.

Political Graveyard date pages during 1793 to 1805 show theFrench Republican date, including the Rural Calendar day name.

Jewish or Hebrew calendar

The Hebrew calendar, codified in the 12th century CE, numbersthe years since the assumed Biblical year of creation.

A common year is twelve lunar months, which comes to about 354days; to make up the difference, some years have thirteen months.

All of the day pages in Political Graveyard show the Jewishor Hebrew dates for that day.

Hebrew days begin and end with sunset. Accordingly, on eachday page, two dates are given, corresponding to the portionsof the Gregorian day before and after sunset.

Further reading

• Juliancalendar
• Gregoriancalendar
• Adoptionof the Gregorian calendar
• BritishCalendar Act of 1751
• OldStyle and New Style dates
• Alaska Day
• FrenchRepublican calendar
• Hebrewcalendar.