Muhammad's first revelation

In Islam, the exact date of Muhammad's first revelation is disputed, but it is generally believed by Muslims to have occurred in 610. According to Islam, while isolating at the Cave of Hira during a retreat to Jabal al-Nour near Mecca, Muhammad was visited by the angel Gabriel, who revealed to him the beginnings of what would become known as the Quran.¹ Thus, at the age of 40, Muhammad's religious career as the "Seal of the Prophets" had begun.

Date of the revelation

The exact date and time of the revelation is not mentioned anywhere. As a result, the exact date is disputed.

The calendar's state during the first revelation

To stop the calendar months from rotating through the seasons, intercalation was employed. This involved the occasional insertion of an extra month (announced at the pilgrimage), ideally seven times in nineteen years. Intercalation was said to have been introduced in 412 AD, and it was borrowed from the Jews; the Jewish official controlling the practice was known as the Nasīʾ.²

When the Arabs adopted the procedure, they used the word nasīʾ to denote the whole system. It was operated in a similar fashion to the Jewish practice, in that the beginning of the year (Muharram) was tied to the spring season.³

Identifying the date of the first revelation

According to the Islamic scholar Safi al-Rahman al-Mubarakpuri, the exact date of this event was a Monday on the 21st of Ramadan and just before sunrise (10 August 610), when Muhammad was 40 lunar years, 6 months and 12 days of age (39 solar years, 3 months and 22 days).