Nanakshahi calendar designed by Pal Singh Purewal to replace the Bikrami calendar. The epoch of this calendar is the birth of the first Sikh Guru, Nanak Dev in 1469 and the Nanakshahi year commences on 1 Chet. New Year's Day falls annually on what is March 14 in the Gregorian Western calendar. The start of each month is fixed. According to Kapel (2006), the solar accuracy of the Nanakshahi calendar is linked to the Gregorian civil calendar. This is because the Nanaskhahi calendar uses the tropical year instead of using the sidereal year which is used in the Bikrami calendar or the
Adoption of the Gregorian calendar to diverge from Gregorian. There will be no difference between the two calendars until 2800. The Greek Orthodox Church of Jerusalem, Russian Orthodox Church, Serbian Orthodox Church, Georgian Orthodox and Apostolic Church, Polish Orthodox Church, Macedonian Orthodox Church and the Greek Old Calendarists did not accept the Revised Julian calendar, and continue to celebrate Christmas on 25 December in the Julian calendar, which is 7 January in the Gregorian calendar until 2100. All of the other Eastern churches, the Oriental Orthodox churches (Coptic Orthodox Church of Alexandria, Ethiopian Orthodox Tewahedo Church, Eritrean Orthodox Tewahdo Church, and Syriac Orthodox Church) continue