The Caliphate - Its Rise, Decline, and Fall, From Original Sources #222852

The reader will bear in mind that the Moslem year, as purely lunar, is eleven days shorter than the solar, and consequently loses about three years in every cycle of a hundred. The lunar month has also this peculiarity, that while, like the Jewish, the date indicates the age Of the moon, the month itself gives no indication Of the season Of the year. The dates have usually been given throughout according to both the Moslem and the Christian notation.