The badí‘ calendar, established by the báb and refined by bahá’u’lláh and the universal house of justice, consists of 19 months each with 19 days. The calendar begins on the vernal equinox, known as naw-rúz, which marks the first day of the bahá'í year, corresponding to March 21, 1844. Key elements of the calendar include holy days, grouping of years into 'váhids' and 'kull-i-shay’, and a system independent from other calendars.