Note 197
From The Invasion of Spain, part of Chapter 51 of the Decline & Fall

The distinction between a proscribed and a tolerated sect, between the Harbii and the people of the Book, the believers in some divine revelation, is correctly defined in the conversation of the caliph Al Mamum with the idolaters or Sabaeans of Charrae, (Hottinger, Hist. Orient. p. 107, 108.)