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 proved unable to keep up with the demand for copies. Catholic states such as France, the Italian principalities, Poland, Spain (along with her European and overseas possessions), Portugal and the Catholic states of the Holy Roman Empire were first to change to the Gregorian calendar. Thursday, 4 October 1582 was followed by Friday, 15 October 1582, with ten days skipped. Countries that did not change until the 18th century had by then observed an additional leap year (1700), necessitating the dropping of eleven days. Some countries did not change until the 19th or 20th century, necessitating one or two further