<P> The Ottoman Empire's Rumi calendar, used for fiscal purposes, was realigned from a Julian to a Gregorian starting on 16 February / 1 March 1917 . The beginning of the year was reset to 1 January starting in 1918 . The numbering of the years, though, remained uniquely Turkish until the Gregorian calendar was introduced for general purposes on 1 January 1927 . </P> <P> In Russia, the Gregorian calendar was accepted after the October Revolution . On 24 January 1918 the Council of People's Commissars issued a decree that Wednesday, 31 January 1918, was to be followed by Thursday, 14 February 1918, thus dropping 13 days from the calendar . With the change, the October Revolution itself, once converted, took place on November 7 . Articles about the October Revolution which mention this date difference tend to do a full conversion to the dates from Julian to the Gregorian calendar . For example, in the article "The October (November) Revolution" the Encyclopædia Britannica uses the format of "25 October (7 November, New Style)" to describe the date of the start of the revolution . </P> <P> Other countries of eastern Europe, most notably Eastern Orthodox countries, adopted the Gregorian calendar in the 1910s or early 1920s . The last country of Eastern Orthodox Europe to adopt the Gregorian calendar for civil purposes was Greece, at the time under military administration following the 11 September 1922 Revolution, with Wednesday 15 February 1923 being followed by Thursday 1 March 1923 . The Soviet decree expressly limited the reform to lay (i.e. non-religious) matters, as did the Greek decree . None of these reforms affected the dates of religious holidays . (See below .) </P> <P> While the civil administrations of Eastern European countries adopted the Gregorian calendar in the 1910s or early 1920s, none of the national Eastern Orthodox Churches have recognised the Gregorian calendar for church or religious purposes . Instead, a Revised Julian calendar was proposed in May 1923 at the Pan-Orthodox Congress of Constantinople (fr). The first churches to start using this calendar did so on 18 September / 1 October . It uses a different leap year rule, modifying a proposal of 1785 in such a way as to maximise the time before its dates start to diverge from Gregorian . There will be no difference between the two calendars until 2800 . </P>

When did greece change to the gregorian calendar
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