The current TV commercial dramatises the redcoated endomorph's relationship with a little girl, who grows into a winsome girl, becomes a mother and ends up as a silver-haired granny (still drinking Coke, rather implausibly, throughout) while the irritatingly jovial figure of Santa never changes.

He's always been there (the advert suggests) - we invented Santa, and he's now been around a whole lifetime. Many people believe it. It's one of the great fake historical inventions. As a Santa website says, "The Santa we all know and love was created for Coca-Cola in 1931 by Haddon Sundblom."

Wrong wrong wrong. The original character was much more interesting. He started life as a figure drawn by Thomas Nast, a Bavarian-born American cartoonist working on Harper's Weekly. In January 1863, while the American Civil War raged on (the Confederates had won the Battle of Fredericksburg a month earlier), Nast created Santa as a spiritually uplifting figure, Stars 'n' Stripes coat, handing out toy puppets to stricken Union soldiers. Nast drew on several European traditions, especially the life of St Nicholas, a fourth-century Byzantine bishop, a legendary figure of flowing beard and robes, who wandered town to town for reasons remaining inscrutable, giving gifts to children who chose the right end of the naughty-nice spectrum.

Nast's German ancestors' fascination for folk tales inspired him to give the ambulant bishop a retinue of elves and dwarfs, busily employed in making toys. This image-making was hijacked by Norman Rockwell for a Saturday Evening Post cover in the 1920s, and reinvented by Sundblom in 1931, using his vastly corpulent self as a model.

It's nicely ironic, though, that the big man's originator should be Thomas Nast. For he was the father of the modern political cartoon, relying on scabrous and startling images rather than lengthy captions. His wit was barbed and, while sticking up for ethnic minorities like American-Indians, he was a shameless bigot; he really hated Catholics and the Irish. It's rather nice to think that the snuggly old sweetie Father Christmas was brought to life by the 1860s equivalent of Dave Brown or Steve Bell. If Nast had been more like them, would he, as the years passed, have pictured the spirit of Christmas growing into a ghastly consumerist folly, exploiting labouring elves, overworking reindeer and grinding the faces of the Cratchit family? I'm afraid that if he had, the Coca-Cola people would have given him a wide berth.