The ninth month of the Islamic calendar (the Hijra). It is a holy month of fasting, celebrating the time at which the Qur'an was first revealed. The month of Ramadhan begins after the sighting of the lunar crescent on the previous evening, so it may begin on different days in different parts of the world. During the Fast of Ramadan Muslims do not eat or drink during the daylight hours. No smoking or marital relations are allowed.