it's 1582 and Pope Gregory the 13th has a huge problem time is broken see according to a millennia old church decree the Feast of Easter must be held on a specific date each year but that date keeps moving it has moved so much in fact that by the 16th century Christians across the world are celebrating Easter four whole days out from when they're supposed to and this is a big deal for Gregory so like some of the greatest Minds that had come before him he set out to control Time by changing the instrument used to
measure it he's going to fix the [Music] calendar say do me a favor and save the date for July 16th would you wait that's today I should have checked my calendar for the earliest humans the passage of time was just something that sort of happened of course the length of days and nights changed with the seasons but beyond that you really did have more important things to worry about like Cave Bears for instance but when the Neolithic period had dawned and humans began to settle down in agricultural communities knowing the time of the year became
a matter of survival because tracking went to plant and harvest your crop was the difference between a year of Plenty and a harsh hungry winter not to mention if you missed your chosen deity's holy day I mean who knows how they might decide to Smite you as time went by the need for an accurate way to track the weeks and months only grew the movement of armies the exchange of goods the terms of office for elected officials all trappings of civilization are underpinned by a Shar understanding of time now the earliest calendars have been found
in places as far apart as Australia and Scotland dating back more than 10,000 years we also know the Sumerians had a calendar as did the Egyptians Assyrians and the Babylonians and so did the earliest Chinese cultures the Mayans the peoples of the indis valley and I think you start to get the idea this was something that was important to everyone for those early civilizations the natural way to measure the passage of time was by the day measured by Sunrise the month measured by moon phases and of course the solar year but they all faced the
same challenge one that the wisest religious and secular Minds would grapple with throughout the Millennia to come you see a lunar month the time it takes for the moon to pass through its phases is roughly 29 1/2 days long so 12 lunar months adds up to about 354 days but it takes the Earth just a little less than 365. to 5 days to make one orbit around the Sun and that math just doesn't add up it's a of around 11.25 days if we're being kind and not just running numbers to the end of the screen
now the answer to this thorny question has been the same for almost every culture who has tackled it just add some more days the practice of adding these intercalary days began as far back as the Egyptians who in 239 BCE adopted a calendar of 12 30-day months with five extra days plus a sixth every four years turns out that whole leap year thing is a pretty ancient idea and over time different cultures chose different ways to add these extra days many of them would group them together such as the Chinese four quarter calendar that inserted
an extra 10day week in certain Summers and the Buddhist calendar that adds an extra 30-day month every few years the ancient Romans would occasionally add an extra month between February and March creating a year that would last 22 extra days this also created an interesting way for Roman politicians to abuse their power however since their terms of office lasted for a calendar year they could just elect to give themselves more time in office by extending the year which led the most famous Roman of all to try and do something about it in 46 BCE Julius
Caesar aided by the astronomer SOI Jus introduced a new calendar with 12 months of 30 or 31 days except for februari us that had 28 he also kept the names of the months as they were although two years later Emperor Augustus decided to change quintilius to Julius in honor of his great uncle and sextius to Augustus in honor of you know himself Caesar's calendar the Julian calendar was was so accurate and the legacy of the Roman Empire so dominant that Europe continued using it for the next 1,600 years that is until Pope Gregory encountered his
problem from the beginning of this episode the Julian calendar was based on a year that was exactly 365.25 days long allowing an extra day to Simply drop into februar as once every 4 years however as astronomers had known for at least a century before Caesar cooked up his calendar the solar year is just a little bit shorter than that as a result too many leap years had been added in and the calendar had drifted off course this mattered for Pope Gregory and the Catholic church because in 325 ad the Council of NAA had decreed that
the 21st of March would be the point from which Easter was determined but by 1582 thanks to Caesar's slapd math the 21st of March was 4 days out from where it had been at the time of the council's decree the work to fix this had actually begun 40 years earlier that's just how long it took mathematicians all across Europe to come up with a solution but by reducing the number of leapers that would arise over the centuries and remov in 10 days from 1582 they did it and from that work the Gregorian calendar was born
it's actually so accurate it gains just one tenth of a day over the course of 400 years and it's the basis of the international standard that we use today though it did take a while for Gregory's calendar to catch on as you might expect the Holy Roman Empire was quick to adopt the Pope's new calendar but the other Christian churches refused to recognize it it took almost 200 years for Protestant Britain to accept it and it wasn't until the start of the 20th century that the Orthodox nations of Russia and Eastern Europe adopted what by
then had become the international standard in fact these were part of the modernization reforms pushed through during the Russian Revolution since it was the Zars who had stubbornly stuck to the old style calendar a zaris legacy that remains a huge headache for historians or anyone trying to cite historical dates who have to keep listing two dates for every Russian historical event and spend valuable minutes of their lives explaining why the October Revolution actually happened in November but I digress of course there are many many other ways you can slice up time take the French Republican
calendar for instance which was based on decimals 10 days to a week 10 hours to a day and 100 minutes to an hour now does that sound confusing well Napoleon thought so too and he tossed it out along with the Republic itself although it did make a brief Resurgence during the Paris commune in 1870 1 another alternate system is the Islamic calendar which is based on a lunar year with no leap days and takes its year one as the date the prophet Muhammad established the first Muslim Community there's also the Hindu and Chinese calendars which
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 zodiac Cycles roughly equal to six solar years oh and another interesting thing the Julian and Gregorian calendars used to be circular we didn't start putting them into grids until the invention of almanacs books of tables that helped you calculate the date and what was going on that day astronomically but one thing remains constant throughout history despite mathematical changes cultural differences and Cosmic Outlook every human culture has grappled with the calendar mapping
the passages of the Moon Sun and planets to know our place within the cosmos we've taken the Clockwork movements of celestial bodies spinning around us at incredible speeds and used mathematics to rationalize their movement mov ments into a system that every person from Kings to generals to Farmers to priests can use to plan something as mundane as when they're visiting the dentist and if you choose to mark your days according to Pope Gregory's plan but would also like to have a great historical time doing it then we here at extra history have got you covered
take it away IRL Matt thank you animated Matt you know if there's one thing that's always bothered me about traditional calendars it's all these blank dates right I mean history happens every day I can assure you of that so isn't it time that your calendar reflected that fact we sure think so which means I am super excited to finally announce what our team has been working on for the past 6 months I give you the 2025 extra history calendar a beautifully designed tool that in addition to the usual functionality you'd expect also includes more historical
happenings on a perday basis than any other calendar we've ever seen seriously we did a lot of research on this thing and because we've made over 700 extra history videos at this point that means we can link directly back to videos about those daily historical happenings it kind of works like this this is the mockup we have right but if you see a picture like this where there's something a little bit extra on there that means that you can go down here and scan a QR code to watch a video about something that happened in
that day of history I mean come on let's see another calendar have that breath of stuff as for the art we wanted to make sure our calendar was not only gorgeous but also tied our extra history style in with some of the classic so we enlisted our longtime illustrator David hoo to take some of the world's most famous art and reimagine it in our Bean art style while also incorporating historical figures that we talk about in our videos this has seriously been my favorite part of this entire process watching what David comes up with it
has been magic they all look amazing and I cannot wait to show you more so if that sounds as cool to you as it does to all of us we urge you to come back our 2025 extra history calendar the kickstarter is live right now and with your help we can turn our date filled dream into a wallmounted reality there's also early bird pricing there and we guarantee if you back us you will get your calendar before 2025 which I imagine is very important in this case with all that said what are you waiting for
friendos to be a part of this historic calendar click here and then once you've selected your tier check out another video here a legendary thanks to kuak Koy Joseph blame Izzy coin Hunter Z Dominic valenciana araly games and Angelo valenciana for being fantastic legendary Patriot it's [Music]