Paul Alvarus wrote the Indiculus luminosus in 854 in response to the executions of a number of C rdoban Christians, beginning with the monk Isaac in 851, who had denounced Muhammad in public. The first half of the treatise offers an extended apologia in defence of the militant actions of these spontaneous blasphemers. In the second half, Alvarus argues at length, on the basis of key passages in Daniel and Job, that Muhammad was a...