Ulum al Qur'an
BEGINNING OF THE REVELATION
The revelation of the Qur'an began in the laila al-qadr of Ramadan (the 27th night or one of the odd nights after the 21st) after the Prophet Muhammad had passed the fortieth year of his life (that is around the year 610), during his seclusion in the cave of Hira' on a mountain near Makka.