AD1900 (1616) and will continue to do so until AD2100 (1816). In that year, the Gregorian calendar's lack of a leap day will cause the Coptic month to advance another day relative to it and it will run from 7 September to 11 September. Coptic leap years are not computed as divisors of four in that calendar's Diocletian era but occur in the year prior to the Gregorian leap year. The Coptic liturgical calendar of the month consists of: Ethiopian calendar In the present-day Ethiopian calendar, Paguemain or Pagume is identical to the Coptic intercalary month, beginning on 6 September and ending on 10 September in common years and 11 September in leap years. Its leap years occur at the same time and its dates will also shift forward one day relative to the Gregorian calendar in AD2100 (2092). The unusual calendar is notably used in Ethiopian tourist information to advertise the country's "thirteen months of sunshine". Mandaean calendar The Mandaean calendar consisting of 12 30-day months, with 5 epagomenals inserted at the end of every 8th month (Mandaic: Šumbulta). These 5 extra days constitute the Parwanaya (or Panja) festival in the Mandaean calendar. See also Egyptian, Coptic, and Ethiopian calendars Babylonian, Zoroastrian, and Armenian calendars Persian and Hebrew calendars Islamic calendar Sansculottides Notes References Citations Bibliography . . . . . Egyptian calendar Months of the Coptic calendar Ethiopian culture