Social media users have been baffled to discover that the iPhone calendar is missing 10 days.
The strange omission was spotted by a sharp-eyed iPhone user who found that the calendar jumps from October 4 straight to October 15 in the year 1582.
In a viral post on X (formerly Twitter) viewed over 49 million times, the user asked: ‘What the f*** happened in October 1582?’
Thousands of social media users flocked to the comments to share their confusion.
One commenter wrote: ‘It means that all of us are 10 days older?’
‘They been keepin us 10 days behind,’ added another iPhone user.
And one commenter jokingly suggested: ‘Someone got knocked into next week – literally.’
Surprisingly, this isn’t caused by some sort of technical glitch or mistake from Apple -and there’s a simple explanation.
Social media users have been baffled to find that the iPhone calendar is missing 10 days between October 4 and October 15, in the year 1582

On the iPhone calendar app, the days from October 5, 1582 and October 14, 1582 are missing entirely, leaving social media users to puzzle over why this might be the case (stock image)

Some confused commenters wondered if this meant they were 10 days older than they had thought
As confused users struggled to understand why October 5 to October 14 had been removed from the calendar app, some of the suggestions were less than helpful.
One commenter offered: ‘Ya so basically time is fake hope this helps.’
Another chipped in: ‘It was a leap year.’
One commenter wryly asked: ‘You don’t remember?’
Other commenters, meanwhile, were more concerned to find out why the original poster had scrolled all the way back to October 1582 in their iPhone calendar.
‘Dude, do you even have a life to scroll down that much,’ wrote one commenter.
Another asked: ‘U scrolled ur calendar that far?’
While one commenter added: ‘How long did it take you to go back 540 years? Were you that bored?’

Other commenters were more confused about why the original poster scrolled back to the year 1582 in their calendar

One commenter asked how long it took to scroll back the 540 years to find this strange omission
In reality, the reason the iPhone calendar is missing 10 days actually goes back even further – to the time of Julius Caesar.
In 45 BC, shortly before his assassination, Julius Caesar implemented what would become known as the ‘Julian Calendar’.
Inspired by the Egyptian astronomers, this new calendar replaced the old lunar calendar with one based on the movements of the Earth around the sun, adding one leap day every four years.
However, although the Julian Calendar was remarkably reliable for its time, it wasn’t quite perfect.
According to the Julian Calendar, the year was 365 days and 6 hours – about 11 minutes and 14 seconds longer than it actually takes for the Earth to orbit the sun.
That might not seem like a lot, but this small difference meant that the date drifted by a day every 314 years.
By the eighth century AD, Christian scholars had already begun to notice that the calendar was becoming increasingly out of sync with the actual passage of the seasons.
But the biggest concern for the Church was that these errors were making it difficult to work out the exact date of Easter.

The origin of the missing days goes back to Julius Caesar (illustrated) who introduced the Julian Calendar in 45 BC. This calendar was about 11 minutes shorter than a solar year, meaning it got out of sync with the seasons over hundreds of years. Pictured: A s

In February 1582, Pope Gregory XIII (pictured) signed a papal bull introducing a new calendar known as the Gregorian Calendar to fix the errors. To introduce this, the church had to skip the 10 days between October 4 and October 15, removing them from the calendar
In 325 AD, at the Council of Nicaea, the church had decreed that Easter should fall on the first Sunday following the first full moon after the vernal equinox, which was March 21 at the time.
However, as the Julian calendar slipped away, the vernal equinox was getting further and further from March 21.
To fix this discrepancy, Pope Gregory XIII signed a papal bull in February 1582, implementing a new calendar which would become known as the Gregorian Calendar.
To bring the spring equinox back to March 21, the church simply cut out the 10 days between October 4 and October 15.
October was chosen for the switch over to avoid skipping any important dates in the Church calendar.
That meant people went from celebrating the feast of St Francis of Assisi on October 4, 1582, straight to October 15 the next morning.
Since protestant and Orthodox European countries were slower to adopt the change, for hundreds of years, travelling across borders in Europe meant jumping back and forth 10 calendar days.
It wouldn’t be until 1752 that the British Empire finally adopted the Gregorian Calendar, finally making it the default timekeeping system for world history.

One commenter joked that users could ‘blame the Pope’ for the fact that their iPhone calendar was missing a few days

One social media user wrote that Pope Gregory XIII ‘deleted 10 days like it was a bad tweet’
On social media, history buffs familiar with the story were delighted to see that the iPhone calendar still reflected this 500-year-old reform.
One commenter wrote: ‘They deleted 10 days like it was a bad tweet. Gregorian calendar update dropped and time got patched.’
‘Imagine going to sleep on the 4th and waking up on the 15th. Rent’s due. You missed your own birthday. Absolute chaos,’ one commenter added.
While another joked: ‘I still remember this day. Slept on October 4 and then the next morning it’s October 15 already. My best sleep ever to this day.’