Read More: Hijri New Year Holiday Announced in UAERead More: The full list of UAE public holidays for 2020What is the difference between the Prophet's migration and the Islamic New Year? But the truth is, that there is absolutely no relationship between the Prophet’s migration and the beginning of the Hijri year, or the Hijri New Year as it was called. According to Islamic scholars, the Hijri calendar did not appear until the era of the second Rashidun Caliphs, Omar Ibn Al-Khattab, and that was in the year 638 AD. Hijri calendarThe scholars pointed out that the names of the months and days in the Hijri calendar were adopted at the end of the fifth century AD, as this was done for the purpose of unifying the lunar months. The Hijri month has either 29 days or 30 days without a leap year.