Why October Is Missing 10 Days In The Year 1582 On Your Phone


If you scroll back to October 1582 on your iPhone calendar, you might notice something strange: it jumps from October 4 to October 15.

Those 10 days didn’t exist! Here’s why.

A Brief History of Calendars

Before 1582, most of Europe used the Julian calendar, which Julius Caesar introduced in 45 BCE.

It was similar to our current calendar, with 12 months and 365 days a year, plus a leap day every four years.

However, there was a small problem with the Julian calendar’s leap year system. It added an extra day every four years, but this wasn’t perfectly accurate.

Over centuries, this caused the calendar to drift out of sync with the solar year.

The Gregorian Calendar Reform

By the 16th century, the calendar was about 10 days off. This was a big deal for the Catholic Church because it affected the date of Easter, which was supposed to fall on the first Sunday after the first full moon following the spring equinox on March 21.

To fix this, Pope Gregory XIII introduced a new system: the Gregorian calendar.

This new calendar skipped the leap year rule in certain century years, making it more accurate.

Erasing 10 Days

To realign the calendar with the seasons, Pope Gregory XIII decided to skip 10 days.

People in 1582 went to bed on October 4 and woke up on October 15.

October was chosen because it didn’t have any major religious events that would be disrupted.

Lasting Effects

This change is why your iPhone calendar, and many others, jump from October 4 to October 15 in 1582.

It’s a quirk of history that reflects a crucial adjustment to our timekeeping system.

So next time you’re scrolling through old dates on your phone, remember: those missing days in October 1582 were a necessary tweak to keep our calendars in line with the Earth’s journey around the Sun.