Celebrating the Twin Holy Birthdays

The Festival of the Twin Birthdays or the Twin Holy Birthdays refers to two successive holy days in the Baháʼí calendar that celebrate the birth of the Báb on the first day of Muharram in the Islamic calendar (20 October 1819) and the birth of Baháʼu'lláh on the second day of Muharram (two years prior, on 12 November 1817).

They are observed on the first and the second day following the occurrence of the eighth new moon after Naw-Rúz, as determined in advance by astronomical tables using Tehran as the point of reference. This results in the observance of the Twin Birthdays moving, year to year, within the months of Mashíyyat, ʻIlm, and Qudrat of the Baháʼí calendar, or from mid-October to mid-November in the Gregorian calendar.

In 2020, the dates are 18 and 19 October.

From the Kitáb-i-Aqdas:

ALL FEASTS HAVE ATTAINED THEIR CONSUMMATION IN THE TWO MOST GREAT FESTIVALS, AND IN THE TWO OTHER FESTIVALS THAT FALL ON THE TWIN DAYS # 110

“This passage establishes four great festivals of the Bahá’í year. The two designated by Bahá’u’lláh as “the two Most Great Festivals” are, first, the Festival of Riḍván, which commemorates Bahá’u’lláh’s Declaration of His Prophetic Mission in the Garden of Riḍván in Baghdád during twelve days in April/May 1863 and is referred to by Him as “the 225 King of Festivals” and, second, the Báb’s Declaration, which occurred in May 1844 in Shíráz. The first, ninth and twelfth days of the Festival of Riḍván are Holy Days (Q and A 1), as is the day of the Declaration of the Báb.

“ The “two other Festivals” are the anniversaries of the births of Bahá’u’lláh and the Báb. In the Muslim lunar calendar these fall on consecutive days, the birth of Bahá’u’lláh on the second day of the month of Muharram 1233 A.H. (12 November 1817), and the birth of the Báb on the first day of the same month 1235 A.H. (20 October 1819), respectively. They are thus referred to as the “Twin Birthdays” and Bahá’u’lláh states that these two days are accounted as one in the sight of God (Q and A 2). He states that, should they fall within the month of fasting, the command to fast shall not apply on those days (Q and A 36). Given that the Bahá’í calendar (see notes 26 and 147) is a solar calendar, it remains for the Universal House of Justice to determine whether the Twin Holy Birthdays are to be celebrated on a solar or lunar basis.”

(Note 138 - From the 1992 edition, pages 224-225)