---
title: "When did a European country last change calendar?"
description: "Greece adopted the Gregorian calendar, the last in Europe to do so, 1923. What happened, why it has not happened since, and whether it plausibly could again."
url: https://atoneplace.net/the-last-time/calendar-change/
site: "At One Place"
---

# When did a European country last change calendar?

**When did a European country last change calendar?: 1923**

Greece adopted the Gregorian calendar, the last in Europe to do so

The Gregorian reform was promulgated in 1582 and adopted piecemeal over 341 years, largely along religious lines — Catholic countries first, Protestant later, Orthodox last. Britain switched in 1752 and skipped eleven days, going from 2 September to 14 September. Russia switched in 1918, which is why the October Revolution took place in November.

- **What:** Greece adopted the Gregorian calendar, the last in Europe to do so
- **When:** 1923
- **Category:** Countries and borders
- **Could this change?:** Not in any foreseeable way. The event is closed.

## Countries and borders

| Question | When |
| --- | --- |
| When did a country last join the United Nations? | 14 July 2011 |
| When was the US Constitution last amended? | 7 May 1992 |
| When did Britain last change its currency system? | 15 February 1971 |
| When did the US flag last change? | 4 July 1960 |
| When was a US state last admitted? | 21 August 1959 |
| When did the size of the US Supreme Court last change? | 1869 |
| When did the Union Jack last change? | 1 January 1801 |

> This page gives a date and never a "years ago". These pages are built as static files, so a computed interval would freeze at build time and quietly become wrong — which on a reference site is worse than making the reader do the subtraction.

## Common questions

### When did a European country last change calendar?

1923 — Greece adopted the Gregorian calendar, the last in Europe to do so.

### What happened?

The Gregorian reform was promulgated in 1582 and adopted piecemeal over 341 years, largely along religious lines — Catholic countries first, Protestant later, Orthodox last. Britain switched in 1752 and skipped eleven days, going from 2 September to 14 September. Russia switched in 1918, which is why the October Revolution took place in November.

## Related pages

- [When did a country last join the United Nations?](https://atoneplace.net/the-last-time/un-member/)
- [When was the US Constitution last amended?](https://atoneplace.net/the-last-time/constitutional-amendment/)
- [When did Britain last change its currency system?](https://atoneplace.net/the-last-time/decimal-currency-uk/)
- [When did the US flag last change?](https://atoneplace.net/the-last-time/us-flag-change/)
- [When was a US state last admitted?](https://atoneplace.net/the-last-time/us-state/)
- [When did the size of the US Supreme Court last change?](https://atoneplace.net/the-last-time/us-supreme-court-size/)
- [When did the Olympics last award medals for art?](https://atoneplace.net/the-last-time/olympic-art/)
- [When did Vesuvius last erupt?](https://atoneplace.net/the-last-time/vesuvius/)
- [When were the Olympic Games last cancelled?](https://atoneplace.net/the-last-time/olympics-cancelled/)
- [When did the last thylacine die?](https://atoneplace.net/the-last-time/thylacine/)
- [When did the last passenger pigeon die?](https://atoneplace.net/the-last-time/passenger-pigeon/)
- [When was a leap year last skipped?](https://atoneplace.net/the-last-time/leap-year-skipped/)
- [Everything, most recent first](https://atoneplace.net/the-last-time/)

## Sources

- Wikidata — Wikimedia Foundation (https://www.wikidata.org/) [CC0 1.0]