The Hijri calendar

The Hijri calendar is a lunar calendar that starts from the Prophet ﷺ's migration to Medina, and it fixes the dates of Ramadan, the Hajj and the feasts.

The Hijri calendar is counted by the moon and begins in the year the Prophet ﷺ migrated from Mecca to Medina. It tells us when Ramadan, the Hajj and the feasts fall, and people say things like the year 1447 AH.

A lunar calendar whose years are counted from the Prophet ﷺ's migration from Mecca to Medina, and which sets the dates of the acts of worship such as Ramadan, the Hajj and the feasts. The reports say that Umar ibn al-Khattab (may God be pleased with him) adopted the Hijra as the starting point of dating, but they differ on why he chose it and on its date, so that needs a second source. The lunar year is about eleven days shorter than the solar year, which is why the seasons of the calendar move through the year. The conversion of dates from Hijri to Gregorian is a derived calculation in the museum, not taken from a source.