Historical detoursSourced
The calendar needed
a better leap-year rule.
Introduced in 1582, the Gregorian calendar adjusted leap years to keep calendar dates closer to the seasons. Countries adopted it at different times.
A calendar is a system
for keeping up with nature.
Summary / translation: Unbubly · CC BY-SA 4.0
Source and reuse details
Gregorian calendar · Wikimedia contributors
Adapted, summarized and translated from the source. Adapted text is also available under CC BY-SA 4.0.
Reviewed: 2026-09-30