Adoption of the Gregorian calendar for secular use occurred in Eastern Orthodox countries as late as the 20th century and some religious groups in some of these countries still use the "old style" (O.S.) Julian calendar for ecclesiastical purposes. The Kingdom of Bulgaria changed from the Julian to the Gregorian calendar during the First World War on 31 March 1916, where the next day was 14 April 1916. 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.
Kartik (month) Kartik (month) Karthikai, Kartika, Karthika or Kartik or Kartika maasam is a Hindu calendar month that typically overlaps October and November. In the Bengali it is the 7th month, Tamil 8th month), Maithili (7th month) and Nepali calendar (7th month), In the reformed Indian national civil calendar, Kartika is the eighth month of the year. It corresponds with the months of October/November in the Gregorian Calendar It is written as "Kartik", "Kārtika", "Kārtak", , maithili: कातिक, , , , , . Kartika (কার্ত্তিক) is the seventh month of the Bengali Calendar. It begins in mid-"October" of the Gregorian calendar. The