The Concise Oxford Dictionary of World Religions (140 page)

). Shortly before the death of the fourth
wak
l
in 939 (AH 329), it was announced that there would be no further Im
m, that the major occultation would occur (
ghaibat-i-kubra
), and that the Im
m would remain hidden until God gave him permission to manifest himself. Meanwhile, the hidden Im
m gives guidance, hears prayers, and intercedes. al-Mahd
is also known as Im
m-i-‘A
r (the Im
m of the Period), al-Muntazar (the Awaited), and
ib al-Zam
n (the Lord of the Age). See also
MU
AMMAD A
MAD