The Start of the Gregorian Calendar: The Missing 10 Days

Before 1582, almost the whole world followed the Julian calendar. It was great when it was first created in 45BC. Only 11.5 minutes off the solar calendar, the 11 months of 30/31 days (except February, which was as it is today). The months weren’t exactly as they are now.

You will be forgiven for second-guessing the months September, October, November and December. After all, Sept means seven, Oct is eight, Nov is nine and Dec is 10—why are they months 9-12 and not 7-10? In the original Roman calendar, they were months 7-10, hence their names. In fact July and August were months five and six and were originally known as Quintus and Sextus and were changed in memory of two great Caesars: Julius and Augustus.

The downside of the Julian calendar is that by 1582 it was 10 days out of line with the solar calendar. Important Christian dates were moving earlier in the year. Easter was traditionally celebrated on the first day of Spring but it started moving into early March and late February. The pope at the time, Pope Gregory XIII had to do something about it.

He issued a papal bull in February 1582 ordering the use of the Gregorian calendar around Europe. It would replace the Julian calendar. It all seems so simple.

By 1582, Elizabeth had been excommunicated by Pope Pius V and refused to follow orders from Rome. She was the head of the church and would not be told what to do by the Roman Catholic pope. England wasn’t the only country to ignore this papal bull and continued to follow the Julian calendar.

It took almost 200 years for England to finally fall in line. This was during the reign of King George II, who’s parliament issued the British Calendar Act in 1751. The whole of Great Britain would go to sleep on September 2, 1752 and wake up the next day but it would be September 14!

In 1752, England lost 11 days but in 1582 it would have only been 10. Those countries that made the change to the Gregorian calendar went to sleep on October 4 and woke up to find it was October 15. It must have been really disorientating for some people. The clocks going back/forward twice a year is disorientating enough!

The benefit of adding the extra month was that the calendar was out with the solar calendar by just 26 seconds. That would only equate to a day every 3,323 days! Much better than the 11.5 minutes.

There are some downsides to the Gregorian calendar—more than the months September-December not really making much sense! The main one is that the year cannot be equally split into quarters and halves. There will always be more days in some parts of the year. It also means that the months start on different days—and that changes every year.

It doesn’t seem like much of a weakness now. In fact, if you know the day a date fell on one year, you can usually work out the day of the week it will fall on the next day. Apart from leap years, it is always the next day on.

However, the changing days has also led to holidays falling on different days of the week. Those that have to fall on certain days, like the Bank Holiday Mondays in the UK or Thanksgiving in America, will see the specific dates change. It can be difficult to predict the dates the next year.

There have been other attempts at changing the calendar. During the French Revolution, the people attempted to switch to what will now always be known as the Revolutionary Convention Calendar. This finished when the revolution ended but it was a simple calendar to understand.

In short, there were 10 days a week, with the rest day on the last day, and 12 months of 30 days a year. To stay in line with the solar calendar, it meant that there were five extra days. These would be known as feast days. What about leap years? These were added to the end of the year.

The calendar has been through many changes and will probably go through changes in the future. When you look at the whole world, you will see that there are many different calendars followed, such as the Mayan and Chinese calendars. Most people go about their day not even thinking about the changes. It does make dating history difficult. In fact, the dates noted can actually be out by a whole year!

I bet you wish I hadn’t written this now!