Ali was the fourth caliph, and the Sunnites in turn looked upon his followers, the Shiahs, as heretics.

In this way there was, in a measure, a continuous opposition of Persian to Arab, despite the mingling of the two in Islam; and the opposition of Persian Shiites to the Sunnites of the rest of the Mohammedan world at this very day is a curious survival of racial antipathy.

These facts are either unknown or not borne in mind by half the Sunnites on whom he might call, and weigh far less with the other half than his hereditary dominion over the Holy Cities, sanctioned by the prescription of nearly four centuries.