Laylat ul-Qadr (Night of Power) is the anniversary of the night on which, according to Islam, the Qur'an was first communicated to Muhammad (see surat Iqra.) It is conventionally taken to occur on the night of the 27th of the month of Ramadan. Its exact date is uncertain, but is known to have been one of the last ten days of Ramadan. It is praised in surat al-Qadr (in the Qur'an): "The Night of Power is better than a thousand months. The angels and the Spirit descend therein, by the permission of their Lord, with all decrees. (The night is) Peace until the rising of the dawn." Muslims often pray extra prayers on this day, particularly night prayer (qiyam ul-layl) and tarawih.