It's 1582, and Pope Gregory XIII faces a significant problem: time itself is broken. According to an ancient church decree, the Feast of Easter must be held on a specific date each year. However, this date has drifted significantly, causing Christians around the world to celebrate Easter four days off from when they should. For Gregory, this was unacceptable, so he set out to solve the problem by changing the instrument used to measure time: the calendar.
Early Calendars and Their Importance
For the earliest humans, the passage of time was just something that happened. Of course, days and nights changed with the seasons, but early humans had more immediate concerns, like survival. However, as humans settled into agricultural communities during the Neolithic period, tracking time became essential. Knowing when to plant and harvest crops meant the difference between a bountiful year and a harsh, hungry winter. Additionally, missing a deity's holy day could have severe consequences.
As civilizations evolved, the need for accurate timekeeping grew. The movement of armies, trade, and political terms all required a reliable calendar. Early calendars have been found in places as diverse as Australia and Scotland, dating back over 10,000 years. The Sumerians, Egyptians, Assyrians, Babylonians, early Chinese cultures, Mayans, and peoples of the Indus Valley all developed calendars.
The Challenge of Timekeeping
The natural way to measure time was by the day, marked by sunrise, the month, marked by moon phases, and the solar year. However, these early civilizations faced a common challenge: the lunar month is roughly 29.5 days long, so 12 lunar months add up to about 354 days. However, it takes just under 365.25 days for Earth to orbit the sun, leaving a discrepancy of about 11.25 days.
The solution was to add extra days, a practice dating back to the Egyptians in 239 BCE. They adopted a calendar with 12 30-day months and five extra days, plus a sixth day every four years, introducing the concept of a leap year. Different cultures found various ways to add these extra days. For instance, the Chinese inserted an extra 10-day week in certain summers, while the Buddhists added an extra 30-day month every few years. The ancient Romans occasionally added an extra month between February and March, extending the year by 22 days.
Julius Caesar's Reform
In 46 BCE, Julius Caesar, with the help of astronomer Sosigenes, introduced the Julian calendar. It featured 12 months of 30 or 31 days, except February, which had 28 days. Caesar's calendar was accurate enough to be used for the next 1,600 years, maintaining the Roman tradition.
Pope Gregory's Solution
By 1582, the Julian calendar had drifted off course, causing significant issues for Pope Gregory XIII and the Catholic Church. The Council of Nicaea in 325 AD had decreed that March 21 would be the reference point for determining Easter. However, by Gregory's time, March 21 was four days off. After 40 years of work, mathematicians across Europe reduced the number of leap years and removed ten days from 1582, creating the Gregorian calendar. This calendar was so accurate it gains just one-tenth of a day every 400 years and became the international standard.
Adoption of the Gregorian Calendar
The Holy Roman Empire quickly adopted the Gregorian calendar, but other Christian churches resisted. It took nearly 200 years for Protestant Britain to accept it, and the Orthodox nations of Russia and Eastern Europe didn't adopt it until the early 20th century. The Russian Revolution pushed through these reforms, as the Tsars had stubbornly stuck to the old style calendar.
Alternative Calendars
Throughout history, various cultures have developed different calendars. The French Republican calendar, for instance, was based on decimals, with 10 days to a week, 10 hours to a day, and 100 minutes to an hour. Napoleon found it confusing and discarded it. The Islamic calendar is lunar-based, with no leap days, and starts from the date Prophet Muhammad established the first Muslim community. The Hindu and Chinese calendars are based on the 361 days it takes for Jupiter to pass through each of the 12 signs of the zodiac, with five of these cycles roughly equal to six solar years.
The Modern Calendar
The Julian and Gregorian calendars were initially circular, but grids became common with the invention of almanacs. Despite cultural differences and mathematical changes, every human culture has grappled with the calendar, mapping the movements of celestial bodies to understand our place in the cosmos. From kings to farmers, everyone has used this system to plan their lives.
The Extra History Calendar
If you're interested in marking your days according to Pope Gregory's plan while enjoying a historical journey, we have exciting news. Introducing the 2025 Extra History Calendar, a beautifully designed tool that includes more historical happenings on a per-day basis than any other calendar. Our calendar links directly to over 700 Extra History videos, providing detailed insights into daily historical events.
Join the Adventure
Our calendar features stunning artwork by our longtime illustrator, David Hoo, reimagining famous art in our unique style. Each month includes historical figures from our videos, making the calendar both informative and visually appealing.
If you're as excited as we are, join us in bringing the 2025 Extra History Calendar to life. The Kickstarter is live now, with early bird pricing available. By backing us, you’ll ensure you receive your calendar before 2025.
Thank you for joining us on this journey through time. Click here to be part of this historic project, and check out another video for more fascinating history.