In which year was the quran brought down ?

Muslims believe that the Qur'an was repeatedly revealed from Allah to Muhammad verbally through the angel Jibrīl (Gabriel) over a period of approximately twenty-three years, beginning in 610 CE, when he was forty, and concluding in 632 CE, the year of his death.Followers of Islam further believe that the Qur'an was memorized, recited and written down by Muhammad's companions after every revelation dictated by Muhammad.

Qur'an - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Koran)

The Quran was not brought down but it was revealed to the Prophet PBUH. The Quran was revealed piecemeal throughout a period of about 23 years. The Prophet received the first revelation in 610CE, in the Cave of Hira