The Hijri date 12 Rabi Awwal (some say 09 Rabi Awwal) is one of twelve months in the Islamic calendar. This is the Islamic birth date of the holy Prophet Muhammad p.b.u.h. He was born in 570 C.E.. and since the Islamic calendar is 354 days long, the Hijri date is pushed back up to 11 days each year. Muslims celebrate this occasion by holding Milad-un-Nabi (translated: birth of the prophet) functions and gatherings throughout the month of Rabi Awwal.
The main thrust of these Milad-un-Nabi gatherings is to remember, observe, discuss and celebrate the advent of the birth and teachings of the holy Prophet Muhammad, p.b.u.h