text: In AD 895 there was another double readjustment of the start of the araji year.   It moved from 1 Frawardin (12 April) to 1 Khordad (11 June).   By AD 1006 the vernal equinox, 15 March, was again coinciding with nowruz, 1 Frawardin.   In that year, therefore, the epagomenai were delayed four months, moving from the end of Aban to their old position at the end of Spandarmad.   This is the calendar for AD 1006/7:
  The gahanbar did not move quite to their old places, because the fifth moved to 20 Day, which was the old 15 Day, thus increasing the interval between the fourth and fifth to eighty days and reducing the interval between the fifth and sixth to 75 days.   The new dates were:
  Medieval era: Jalali calendar
  In AD 1079, by the order of the Jalal Al-Din Shah Seljuqi, the Islamic Calendar (which was and is based on the lunar system) was replaced in Persia by the calendar of Omar Khayyam and was called the Jalali Calendar. Khayyam and his team had worked 8 years in Isfahan, the capital of Iran during the Seljuq dynasty. The research and creation of the Khayyam calendar was financially supported by Jalal Al din Shah. Khayyam designed his calendar in which the beginning of the new year, season and month are aligned and he named the first day of the spring and the new year to be Norooz (also spelled Nowruz). Before Khayyam's calendar, Norooz was not a fixed day and each year could fall in late winter or early spring.