Calendar Reforms and Adoptions
The moments when countries changed calendars, from the Gregorian reform of 1582 to Turkey in 1926, with the dates that were skipped. 14 entries.
Gregorian reform of 1582
24 February 1582...Pope Gregory XIII's bull Inter gravissimas, dated 24 February 1582, ordered that Thursday 4 October 1582 be followed by Friday 15...
Protestant German states and Denmark-Norway, 1700
1700Most Protestant states of the Holy Roman Empire, together with Denmark-Norway, switched in 1700 by following 18 February with 1...
Swedish calendar, 1700–1712
1700Sweden planned to reach the Gregorian calendar gradually by omitting every leap day from 1700 to 1740. It dropped the 1700 leap...
British calendar change of 1752
Calendar Act 1750...Under the Calendar (New Style) Act 1750, Great Britain and its colonies, including those in America, made Wednesday 2 September...
Alaska calendar change, 1867
1867When the United States bought Alaska from Russia in 1867, the territory changed from the Julian calendar and from the Asian side...
Japan's adoption of the Gregorian calendar, 1873
1873The Meiji government replaced the traditional lunisolar calendar with the Gregorian one with only weeks of notice: the 3rd day of...
Korea's adoption of the Gregorian calendar, 1896
1 January 1896Korea switched from the lunisolar calendar to the Gregorian calendar as part of the Gabo reforms, taking effect on 1 January...
China's adoption of the Gregorian calendar, 1912
1 January 1912The new Republic of China adopted the Gregorian calendar from 1 January 1912, numbering years in the Minguo era. Warlord rule...
Bulgaria's calendar change, 1916
1916Bulgaria became the first Orthodox country to adopt the Gregorian calendar for civil use, following 31 March 1916 with 14 April...
Russia's calendar change, 1918
1918A decree signed by Lenin made Wednesday 31 January 1918 followed by Thursday 14 February. This is why the October Revolution of...
Greece's calendar change, 1923
1923Greece was the last European country to adopt the Gregorian calendar for civil use, following 15 February 1923 with 1 March. The...
Turkey's calendar reform, 1926
1 January 1926The Ottoman Empire's Rumi civil calendar was aligned with Gregorian dates in 1917 but still numbered its years from the Hijra. As...
Soviet work-week calendar
1929–1940From 1929 the Soviet Union replaced the seven-day week in workplaces with a continuous five-day week, the nepreryvka, with...
Thailand's new year change, 1941
1941Thailand moved the start of its official year from 1 April to 1 January in 1941 to align with international practice. As a result...