Interest in Mary Magdalene has been growing for three decades; speculation about her has been active for well over 1,000 years. The West has made Mary Magdalene a prostitute, Jesus’s consort, and the flawed mother of a divine bloodline for diverse reasons, all with varying degrees of seriousness. Since the release of Dan Brown’s “Da Vinci Code,” some of my colleagues in the discipline of New Testament scholarship, as well as a number of other writers who – scenting popular interest – claim a sudden expertise in that field, have contributed many articles and books to the debate about Mary. With the release of the film adaptation of the book this Friday, no doubt many more will follow. But allowing ourselves to obsess over the legends of Mary Magdalene obfuscates what there is to be learned from the historical record.

Today we are passing through a crescendo of interest, typical of patterns many centuries old, rather than witnessing a sudden aberration. And the fact that the major elements compiling the “new” picture of Mary Magdalene have been brought together now in the way they have been shows us more about ourselves than her.

The ideas of Mary the prostitute, Mary the consort of Jesus, and Mary the mother of his child have been a long time coming. Pope Gregory the Great preached about Mary Magdalene in 594, identifying her with an anonymous woman who wiped Jesus’s feet. Because that unnamed person – clearly not Mary Magdalene according to the text of Luke 7 – is described as “sinful,” Pope Gregory portrayed Mary Magdalene as a prostitute. The aim of this inventive harmonization, however, was not to demean her or to write history. Rather, she becomes the image of the impatient lover in the Song of Songs, and her desire is compared to the restless love a monk rightly feels for God as he lies in his bed at night. The material linkage of Mary Magdalene to the world of the flesh was beautifully exploited by Pope Gregory to convey the need to transcend this world and discover the same passion for the divine that she learned. Mary Magdalene revealed the necessity for penance, and also its victory. As Pope Gregory said, “In paradise a woman was the cause of death for a man; coming from the sepulcher a woman proclaimed life to men.” Medieval legend as well as modern fiction eventually lost the balance of imagery that Pope Gregory achieved, and emphasized Eve’s sin at the expense of the Magdalene’s announcement of salvation. Eventually, Mary Magdalene’s prostitution became a more established “fact” than her witness to Jesus’s resurrection – the one datum all the Gospels stress.

Mary Magdalene became a prostitute five centuries after her death. Getting her into Jesus’s bed took longer. By the 13th century, a late form of Gnosticism flourished in the West, chiefly in the south of France and in the Rhineland of Germany. Known as the Alibigensians (after the city of Albi in France) or the Cathars (perhaps from the Greek term katharos, “pure”), they insisted on a strict separation between this world and the realm of spirit. That led to their notion that sins of the flesh, while regrettable and to be outgrown before one’s death, were only to be expected. Even Jesus as a person of flesh had to be distinguished from the spiritual Jesus, the Christ. But of what sin could Jesus have been guilty?

Mary Magdalene came ready-made as a sinner, given the legends regarding her trade as a prostitute that had circulated for centuries. From there it was a short step to make her into Jesus’s concubine. Their relationship symbolized human weakness, and gave Jesus a sin that did not involve him in violence. Pope Innocent III was outraged, although his vehemence may have had more to do with the Cathars’ denial of papal authority (as part of the fallen nature of this world) than their peculiar teaching about Jesus and Mary. Pope Innocent declared a crusade against the Cathars, and the result has been called the first European genocide. On the feast of St. Mary Magdalene, July 22, 1209, 15,000 people from the town of Beziers were slaughtered; a chronicler rejoiced “that these disgusting dogs were taken and massacred during the feast of the one that they had insulted.”

The Cathars were eventually wiped out during the course of successive persecutions.The crusaders seemed to triumph over any suggestion that Jesus might have sinned, with Mary or anyone else.Yet centuries later the notion persists. Once suggested, the idea cannot be disproved, although it is historically implausible that Jesus was formally married. He just did not have the means to provide a wife with a stable living near her family, a requirement of Judaic law in his time.

The prolonged courtship of legend presaged an amazingly long period of gestation. In 1982, “Holy Blood, Holy Grail” made the child of Jesus by Mary Magdalene the great secret of Western history; other books took the theme up before Mr. Brown put it into the most easily digested form yet. Still, this genetic French connection is not the first to have been proposed. Keepers of a tomb in Srinagar, Kashmir, have claimed it to be that of Jesus since the 19th century, as have those responsible for a tomb in Shingo, Japan, since 1935; in both cases the allegations put Jesus’s blood in the veins of local worthies.The French bloodline has come a bit belatedly, for all its celebrity, and indirectly, by association with Mary Magdalene’s alleged tombs in Vezelay or Saint-Maximin (depending on the legend you choose). In any case, before endorsing this Merovingian version of Jesus’s family tree with enthusiasm, readers might want to keep its source in mind. The author of the claim, Pierre Plantard, was so fixated on racial purity that the Nazis in occupied Paris interrogated him for his unauthorized anti-Semitic activities in 1941. That was 15 years before he founded the Priory of Zion, of “Da Vinci Code” fame.

None of these portraits of Mary Magdalene can be definitely disproved, however unlikely they are, because historical reason cannot prove negative assertions, especially when evidence is scarce. From a distance of 2,000 years, how could it be demon strated that any unattached woman who followed Jesus was never a prostitute, never had sexual relations with him, and could not have carried his child?

Those are matters for speculation rather than history. Yet in the case of Mary Magdalene, speculation has spawned legend, and legend has eclipsed history. For beneath the legend, across the centuries, woven into tales told during the Middle Ages and spun out in their postmodern progeny, the underlying facts about Mary Magdalene – clearly reflected in the Gospels of the New Testament – have proved durable. She is the only person in the Gospels named as the recipient of Jesus’s exorcism (and as being treated several times). She is the premier case of a woman who engaged in the ritual of anointing, practiced by many women in Jewish antiquity and embraced by Jesus himself to convey forgiveness of sin and healing. And the role of her vision at the tomb of Jesus as the gateway to belief in his resurrection has been endorsed by generations of scholars from many schools of thought.

Exorcism, anointing, and resurrection were not incidental concerns within the evolution of Christianity. Exorcism was the principal means of discerning and dealing with evil (not merely sexual proclivities) within the human heart – and without the special effects of modern fantasy. Anointing, whether in canonical or Gnostic sources, involved sanctifying a person’s entire body. Resurrection stood at the end, not only of Jesus’s life, but also of human destiny. In choosing to focus on what we can never know about Mary Magdalene to the exclusion of what history patiently shows us, we ignore her spiritual inheritance. Legend makes her the icon of sinfulness, leveling her to the cliche of the harlot, the would-be bride, the broken mother. History speaks of Mary Magdalene in connection with release from evil, sanctification, and realizing the triumph of eternal life over death. Since the Middle Ages, legend has trumped history. Maybe it will be history’s turn soon, if our “postmodern” credulity can outgrow its addiction to medieval legend.

Mr. Chilton’s most recent book, “Mary Magdalene: A Biography,” is available from Doubleday.