Thai lao dating
Yet, the Thai calendars for some reason have fixed the difference between their Buddhist Era (BE) numbering and the Christian/Common Era (CE) numbering at 543, which points to an epochal year of 544 BCE, not 545 BCE.
It is unclear from where, when or how the Metonic system was introduced; hypotheses range from China to Europe.Eleven extra days are inserted in every 57 years, and seven extra months of 30 days are inserted in every 19 years (21 months in 57 years).This provides 20819 complete days to both calendars.In Thailand, the name Buddhist Era is a year numbering system shared by the traditional Thai lunisolar calendar and by the Thai solar calendar.The Southeast Asian lunisolar calendars are largely based on an older version of the Hindu calendar, which uses the sidereal year as the solar year.In all Theravada traditions, the calendar's epochal year 0 date was the day in which the Buddha attained parinibbāna.
However, not all traditions agree on when it actually took place.
Various regional versions of Chula Sakarat/Burmese calendar existed across various regions of mainland Southeast Asia.
Unlike Burmese systems, Kengtung, Lan Na, Lan Xang and Sukhothai systems refer to the months by numbers, not by names.
The calculation methodology of the current versions of Southeast Asian Buddhist calendars is largely based on that of the Burmese calendar, which was in use in various Southeast Asian kingdoms down to the 19th century under the names of Chula Sakarat and Jolak Sakaraj.
The Burmese calendar in turn was based on the "original" Surya Siddhanta system of ancient India (believed to be Ardharatrika school).
The intercalary month not only corrects the length of the year but also corrects the accumulating error of the month to extent of half a day.