Pagans and Christians by Robin Lane Fox (Knopf: $35; 784 pp., maps)

The stereotype of late-night TV fare presents the success of Christianity in the Roman Empire as a matter of overwhelming support by the common people for a persecuted and pure faith.

The real picture is more complicated--involving centuries of give-and-take and, at least initially, a good deal of popular hostility. During the course of this century, scholars have developed two main approaches to the question of Christianity’s eventual success.

The first looks at the pagan environment in which the new faith developed in order to discover the common needs and aspirations that, eventually, Christianity satisfied better than other alternatives.

The second focuses on the dynamics of Christian growth. Here, the missionary zeal of the new faith and the vigor of its apologetic tradition account for a significant expansion by the beginning of the 4th Century.

A turning point in both approaches occurred during the turmoil of the 3rd Century, when invasions on an unprecedented scale, plague, an endless series of civil wars and ruinous inflation all combined to shatter the empire’s peace and prosperity. The resulting insecurity accelerated the search for an afterlife and redemption by a personal, all-powerful deity.

In this fresh study, Oxford’s Robin Lane Fox calls both of these trends into question. Drawing on papyri and inscriptions uncovered in recent decades, he concludes that neither a great ebb tide of traditional cults nor a vast expansion of converts can account for the success of Christianity.

Rather, he concludes, the bulk of the credit must be given to the emperor Constantine the Great, whose conversion by the miraculous Vision of the Cross in AD 312 proved decisive to Christian fortunes.

Such a nutshell account scarcely does justice to the rich store of learning in these pages. Dividing his study into three large sections, Lane Fox deals with the social setting of traditional pagan cults, the novelty of Christian values in this setting and the impact of a Christian emperor.

Lane Fox’s scholarship is immense, his interests wide ranging. He moves easily over the millennium that separates Homeric poetry from the age of Constantine, combining a depth of detail with a graceful and engaging prose style.

His fresh and imaginative approach is reflected in such chapter titles as “Seeing the Gods” and “Language of the Gods,” dealing with pagan epiphanies and oracles, and “Living Like Angels” and “Visions and Prophesy,” on Christian aspirations and sense of the divine. The “Visions” chapter in particular is a remarkable tour de force, combining intellect, attention to scholarly detail and genuine insight.

Yet for all its erudition, this is a book that relies--unnecessarily--on the old magician’s standbys of smoke and mirrors to make its point.

Like a Philadelphia lawyer, Lane Fox begins by denying on technical grounds the validity of a major proposition--such as a growth of pagan “anxiety” or a Christian “winning of the countryside”--only to subsequently accept its substance when no one is looking. Thus, after extensive documentation laced with denials that there was any such thing, we learn both that “a concern for life beyond the grave was perhaps more evident” in the 2nd Century than previously and that there was a greater tendency to merge gods into a single “Supreme Deity”--all of which might have been abetted by an “anxiety which was widespread, though not universal.”

A pretense of taking on the profession’s sacred cows may keep the reader’s attention. But after only a few of these shell tricks, Lane Fox’s sacred cows start to look more like bull.

The attentive reader begins to notice things. It is not until almost the end of his study, for instance, that Lane Fox first deals with the concurrent disasters of plague, invasion and inflation (civil war he never touches) that cast such a shadow over his topic. He gives them two paragraphs.

The effect is similar to an analysis of 20th-Century American attitudes that never mentions World Wars I and II, Vietnam, Watergate or the assassination of John Kennedy.

Some of Lane Fox’s pyrotechnics can be attributed to a mere striving after novelty. Such, for instance, would be his assertion that St. Paul was the cause of all future Roman persecution of Christians--this based on his own assumptions about what Paul might have said in a trial before Nero, for which no record exists.

Yet one suspects as well that Lane Fox emphasizes the suddenness and novelty of Constantine’s change in order to have a suitable counterpart to his earlier study of Alexander the Great, with whom he compares the first Christian emperor on several occasions. In this way, he creates two bookends, so to speak, of the ancient world.

A good editor, or a hard final look by Lane Fox himself, could have vetted this book of about 50 pages and made its accomplishments indisputable. As it stands, however, there is a question of the extent to which these sorts of high jinks will affect its usefulness. Readers with sufficient background to know the tricks will gain much from Lane Fox’s erudition. The general reader, however, will have to approach this book warily, with both hands firmly on his mental wallet.