eli5 how did the whole world come to use one calendar

Question

Did everyone attend a meeting and just agree “today is (certain date), and we’ll go forward from there”?

In: 1

Answer 1

Kind of.

Pope Gregory XIII proposed the calendar in 1582. In October the countries that accepted the pope’s authority basically agreed to skip 10 days so holidays like Easter would line up better with the times of year they occurred at in ancient times.

Countries that didn’t respect the pope’s authority took significantly longer. It took until 1752 for the US colonies to use the Gregorian calendar and it took Russia until 1918 to begin using it!

Edit: got my Roman numerals wrong 🙁