They appear to have fought on most questions, but one cause of conflict was paramount: Christology. During the second century the church was constantly tormented by the problem of reconciling the rigid monotheism inherited from the Jews with the divine honours that were unquestioningly paid to Christ. The solution that Hippolytus proposed followed in general the doctrine of the Fourth Gospel: God from before creation has begotten[46] from Himself His Logos, itself divine. This doctrine rests on speculative metaphysical premises that are none too easy of comprehension; to many thinkers in the second century it seemed either (_a_) to subordinate the Son to the Father in such a way as to detract from the Son’s true divinity, or (_b_) to make of the Son an independent deity and so destroy monotheism. Hippolytus endeavoured to avoid both extremes, but with what success specialists—ancient or modern—are unable to agree; it must be remembered, however, that he wrote as a pioneer in an age when the real questions were not yet clearly stated, let alone answered, and that he employed a philosophy originally devised for a very different purpose. The most popular alternative to his theory was what is rather cumbrously known as “modalistic monarchianism”; this was quite within the grasp of the most unphilosophical, since it disregarded all metaphysical refinements. It argued: “We worship Christ as God, and God is One. Therefore Christ is God and God is Christ; ‘Father’ and ‘Son’ are only titles that describe the same Person in different aspects or ‘modes’”. Later on this modalism was regarded as heresy of the most extreme type, but even in the late second century it was widely taught and was uncondemned; in part the church authorities wished to preserve peace above all things and in part they were really in doubt as to the points at issue. Many teachers, to be sure, attacked it violently and none with greater passion than Hippolytus, who at the beginning of the third century was making the Roman church hot with his invectives. But, despite him, when Sabellius, the great apostle of modalism, came to Rome he was received cordially by Zephyrinus and Callistus. Still, even Hippolytus was forced to admit that Sabellius was an honest and open-minded man, and one with whom he could argue so frankly that he had great hopes of converting him. But Callistus interfered. Not that he himself was quite a modalist; his own Christology, while having strong modalistic leanings, was saved from downright modalism by dexterous qualifications. But he regarded Hippolytus’s doctrine—which he probably could not really understand—as the worse of the two evils. So Sabellius, finding the two great Roman leaders at loggerheads, reverted to his former position. To Hippolytus this was the last straw and he publicly denounced Callistus[47] as a heretic. Callistus retorted by hurling at Hippolytus the final insult: “Ditheist!” The result was a schism.