"It is believed," writes Lieut.-Col. P. M. Sykes, "that the twelfth Imam never died, but in A.H. 260 (873) disappeared into miraculous concealment, from which he will reappear on the Day of Judgment in the mosque of Gawhar-Shad at Mashhad, to be hailed as the Mihdi or `Guide' and to fill the earth with justice." ("A History of Persia," vol. 2, p. 45.)