Santa: A life. By Jeremy Seal

A long sleigh-ride from Asia Minor to the mall

Father Christmas was the pioneer of celebrity endorsement. Just as David Beckham lends his name to sunglasses and boots, Saint Nicholas, a fourth-century Christian from Myra, now Demre in Turkey, has down the ages annexed his image to sell presents of every description.

The big difference is that while the England captain has made his fortune by clever marketing, Nicholas hasn't seen a cent as he has looked down at countless makeovers performed on his memory. One Japanese department store even managed to mark Easter by nailing him to a crucifix above the entrance.

His very name has been corrupted. In Dutch, he began as Sint Nicolaas, rendered as Sinterklass and then transformed on the international shop floor to Santa Claus.

Why, though, did so much attention light on this saint, one of many to receive his halo in the persecuted early centuries of the Christian church? We know, as Jeremy Seal discovers when he sets off in search of the real person behind Father Christmas, very little indeed about Saint Nicholas. According to Seal, who makes the transition effortlessly from travel writer to explorer of religious legends, it all comes down to a single story recorded by the chronicler Symeon, and widely disseminated in the young Christian church and beyond.

A nobleman had fallen on hard times and, since he could find no suitors for his impecunious daughters, decided to sell them into prostitution. God, however, had other plans and sent Saint Nicholas to their aid. He went to their house at night and, not wanting to be identified, threw a bag of gold in the window, giving the eldest daughter a dowry to make marriage possible. He did it twice more, but on the third visit was apprehended by the father. Nicholas swore him to secrecy.

Here are all the elements of the Christmas story that my children still believe in: the hooded figure who comes by night, eschewing the front door, to bring unexpected gifts for the young. How we travelled from a simple story of helping out a needy family to Santa in every shopping-mall grotto is the theme of Seal's biography. Some of this journey has its own momentum - the stories we treasure are dancers to the music of time; they adapt to circumstances.

There is also manipulation. Those who wish to make Santa Claus as profitable a symbol of Western capitalism as McDonalds need to lose his back story as a Christian saint in case it puts off consumers in lands of other faiths.

Into his tale, Seal weaves observations of his own small daughters, their faith in Father Christmas and its gradual erosion. It makes for a complicated narrative structure, but he never falters. Best of all, in territory so scared by excess, cheesiness and empty words, he manages both to entertain and enlighten, and so produce a perfect antidote to the contemporary Christmas.

Peter Stanford's life of the Devil is published by Arrow