II. 227, apud Dozy, iii.
342. Ibn Hazm was, says Dozy, “a
strict Moslem, averse to judging divine questions by human
 Al Makkari, ii. 293.
 Miss Yonge, p. 87, says
the Arabs called him Sham Yakub,
but what authority has this statement?
In a country where literature and the arts were so keenly cultivated, as they were in Spain during the time of Arab domination, and where the rivalry of Christian, Jew, and Moslem produced a sustained period of intellectual activity such as the world has rarely seen, controversial theology could not fail to have been largely developed. But the books, if any were written, from the Christian or Moslem standpoint, have all perished, and we have only such slight and unsatisfactory notices left to us as those already quoted.
In estimating, therefore, what influences the rival religions of Spain had upon each other, we are driven to draw such inferences as we can from the meagre hints furnished to us by the writers of the period; from our knowledge of what Christianity was in Spain, and Mohammedanism in Africa, before they were brought into contact in Andalusia, compared with what they became after that contact had made itself felt; and from the observed effects of such relations elsewhere. Upon a careful consideration of these scattered hints we shall see that certain effects were visible, which, had the amalgamation of the two peoples been allowed to continue uninterruptedly for a longer period, and had there been no disturbing element in the north of Spain and in Africa, would in all probability have led to some marked modification in one or both religions, and even to their nearer assimilation.
HERESIES IN SPAIN.
Such mixtures of religions are by no means without example in history. The Sabians, for instance, were the followers of a religion, which may have been a cross between Judaism, Christianity, and Magianism. But Mohammedanism itself has furnished the most marked instances of such amalgamation. In Persia Islam combined with the creed of Zoroaster to produce Babyism; while in India Hinduism and Mohammedanism, fused together by the genius of Nanak Guru, have resulted in Sikhism.
It may be said that Mohammedanism has been able to unite with Zoroastrianism and Hinduism owing to their very dissimilarity with itself, whereas Christianity is too near akin to Islam to combine with it in such a way as to produce a religion like both, and yet different from either. Christianity and Mohammedanism, each have two cardinal doctrines (and two only) which cannot be abrogated if they are to remain distinctive creeds. In one of these, the unity of God, they agree. In the other they do, and always must, differ. The divinity of Christ on the one side, and the divine mission of Mohammed on the other, are totally incompatible