Mustali died after a reign of about four years; and some historians record, as a truly remarkable circumstance, that he was a Sunnite by creed, although he represented a shiite dynasty.
"History Of Egypt From 330 B.C. To The Present Time, Volume 12 (of 12)"
S. Rappoport
Around the body of the mosque runs a fine inscription in Kufic letters, and from the fact that the name of Ali is joined with that of the Prophet in the profession of faith, we may argue that this mosque was built during some Persian occupation, and was a shiite mosque.
"Southern Arabia"
Theodore Bent Mabel Bent
The Ismailians may be best regarded as one of the several sects of shiites, who originally were simply the partisans of Ali against Omar, but by degrees they became identified as the upholders of the Koran against the validity of the oral tradition, and when, later, the whole of Persia espoused the cause of Ali, the shiite belief became tinged with all kinds of mysticism.
"History Of Egypt From 330 B.C. To The Present Time, Volume 11 (of 12)"
S. Rappoport