The monophysitism of the fifth century had its roots in the past as well as in the _a priori_. In the previous chapter we treated it as a phase of philosophic thought and reviewed the metaphysic on which the heresy rests. In the present chapter its relations as a historical system of religious thought are to be exhibited. As such, it owes much to outside influences. Much in the monophysite mode of thought and many of its specific doctrines can be traced either to other ecclesiastical heresies or to pagan philosophies. The fact of this double derivation deserves to be emphasised. It refutes the charge of inquisitorial bigotry, so frequently levelled against the theologians of the early centuries. The non-Christian affinities of the heresy account for the bitterness of the controversy to which it gave rise, and, in large measure, excuse the intolerance shown by both parties. Heresies were not domestic quarrels. Contemporaries viewed them as involving a life and death struggle between believers and unbelievers. Christianity can afford to be tolerant to-day. It has an assured position. Its tenets are defined. Christians can almost always distinguish at a glance errors that threaten the essentials of the Faith from those that do not. In the fourth and fifth centuries the case was otherwise. Christianity was then one among many conflicting systems of religion. Its intellectual bases were as yet only imperfectly thought out. Any doctrinal error seemed capable of poisoning the whole body of belief. Heresy, so the orthodox held, was of the devil. No charitable view of it was allowable. That uncompromising attitude was, to a large extent, justified because many articles of the heretical creeds were of purely pagan origin. Given similar conditions to-day, our easy tolerance of opinion would disappear. If Islam, for instance, were to-day a serious menace to the Faith, Christians would automatically stiffen their attitude towards monophysite doctrines. Toleration of the false Christology would, under those circumstances, be treason to the true. The Church of the fifth century was menaced from many sides. Monophysitism was the foe at her gates. That heresy was not a variety of Christianity. It was a semi-pagan theosophy, a product of Greek and oriental, as well as of purely Christian speculation; therefore it was anathema to the orthodox. THE ELEMENTAL FORMS OF CHRISTOLOGICAL ERROR--DOCETISM AND EBIONITISM We propose to begin the study of the antecedents of monophysitism by examining those of a Christian or semi-Christian character. For that purpose it will be necessary to give a brief sketch of the early heresies in so far as they bear on the Christological problem.