... Abu Bekr, founder of the dynasty of the Almavorides, seems to have begun with a sort of religious reformatory movement, carried on, of course, at the point of the sword, whilst Yusuf or Youssef (Joseph), who ultimately succeeded him, was originally his lieutenant, and being left in charge during an expedition of his master's across the Atlas, acquired the whole north-west of Africa, up to and beyond Algiers, and established himself, ere the return of the other, too firmly to be dislodged.  Both were of the native tribes, though Mahometans, and it has been usual, therefore, to call this portion of the history of Algeria. (The Life and Adventures of Jules Gérard &c., 1857)