Mother of God, By Miri Rubin

Nothing proves the thesis of this new history of the Virgin Mary – that she has conquered the imagination of generations in the most profound way – better than the current Byzantium exhibition at London's Royal Academy. Depicted in silver and gold, in egg tempura, enamels and jewels, the Byzantine icons on display reveal a Mother of God who is majestic and dominant.

Contrast that image with the Mary that so many of us recognise from the art of Western Europe and you have an idea of the paradoxical nature of this woman. In Renaissance paintings, often of the Annunciation, when the Angel Gabriel announces to Mary that she is to conceive a son, she is beautiful, full of grace – as the angel called her. Or think of the most celebrated nativity scenes, where she is the embodiment of maternal love. As Miri Rubin highlights in Mother of God, the genius of Christianity was to forge in Mary a woman who could be adapted over and over again to represent very different traits, beginning with the mystery of her being both virgin and mother. To use Shakespeare's description of another queen, this queen of heaven is a woman of infinite variety.

Rubin's account is not a theological examination but a cultural history. In her attempt at chronicling Marian devotion, she reminds us of how remarkable it is that such a diverse cult developed, for it began with little substance. Mary is limited in the New Testament to the Annunciation, the Visitation of Mary to her cousin Elizabeth, the birth of Christ, the flight of Mary, Joseph and their child to Egypt, two incidents in the temple in Jerusalem, a wedding feast at Cana, and the Crucifixion. Finally, in the Acts of the Apostles, she dies, goes to heaven and disappears.

From this came a woman who dominated the development of Christian belief and culture almost as much as Christ. The hand that rocked the cradle soothed and inspired multitudes of believers. By 431, her status was confirmed by a church council which declared her to be "Theotokos", a Greek word which means God-bearer. For God was no longer an abstract idea, or something so beyond us, as Judaism had thought, but was to be found in Jesus, a person. If Jesus was God incarnate, his mother must be uniquely blessed.

Christians put her at the centre of their lives and in worship. Rubin, professor of medieval and early modern history at Queen Mary, University of London, is particularly strong in Mary's growing influence in the Middle Ages. Marian devotion developed in monasteries where she was the focus of much of the liturgy. The cult spread to aristocratic families, being thought suitable for women, and later became apparent in all walks of life. As the population grew so did the building of churches, many dedicated to the Virgin. Just how widespread was her cult was signalled by Peter Ackroyd in his recent Sacred River, when he walked the banks of the Thames and found more than 50 churches, chapels and chantries devoted to the Mother of God.

Rubin is not the first to write an account of Mary but, 30 years after Marina Warner's Alone of All Her Sex, this volume offers new insights. It is particularly welcome that she makes use of women mystics: clear evidence that the cult was not a male construct. Mary became a model of the perfect disciple and nurturer. Rubin also interprets the devotion of men, from priests to monks and mendicant friars, as the love of those who have lost their own mothers through early dedication to the religious life. She also alludes to the cult's usefulness in feminising an otherwise very male religion, focused on God the Father and God the Son.

Rubin moves from the odd and amusing to the deeply disturbing. A constant theme is the way in which Mary, a Jewish mother, was used in the first 1,500 years of Christianity as a weapon to attack the Jews. As they refused to accept that Jesus was God incarnate, and Mary the means through which God was made flesh, she was held up as proof of the Jews' error. Stories abounded whereby she was the means for conversion and persecution. Muslims, in contrast, warmly embraced her. Rubin notes there are far more references in the Koran to Mary than in the Gospels.

Others also rejected the notion of a fleshy God. The Manicheans viewed with disgust the notion that God had been born of "a filthy womb". Even though Christianity is associated today with inhibitions, particularly sexual, this history reveals how important Mary has been in overcoming prejudices about the body. Something that contained the Godhead must in essence be good. Sometimes this revelling in the body makes us prudish 21st-century creatures uncomfortable. The obsession with her breasts and milk seems particularly odd, and the account of St Bernard of Clairvaux and his vision of drinking Mary's milk seemed to verge on a scene from Little Britain.

What this book does not get to grips with is the true importance of Mary in Christian belief. Rubin gets part of the way there, but does not discuss that for so many Christians Mary is not only a human but a spiritual route to her son. As a mother she is much more accessible than a God, even a God made man. That, perhaps, is something for a book about belief rather than a history.

If anything, this book could have done with more history. There is remarkably little on the iconoclasm of the Reformation, or of the Protestant Elizabeth I's invention of herself as the replacement virgin queen, too brief references to the many 19th-century apparitions of the Virgin Mary, nothing on the Marian cult of Poland or the Marist theology of its most famous son, John Paul II. But for its insights into the medieval world and the woman who dominated so much of its culture, this is a welcome, illuminating and at times disturbing history.

Catherine Pepinster is editor of 'The Tablet', the Catholic weekly