Some of this is blamed on American advertising, especially by the Coca Cola Company, which is sometimes credited with inventing the modern image of Santa and sometimes accused of perverting the real, more saintly image. Before I tell you that neither is true, let me disclose that I still own slightly less than two shares of Coke stock as a result of an Internet typo I made several years ago. Now that my interest in the Company is acknowledged, I can say it -- Coke isn't guilty. For a full-scale exposition on Coke's Christmas advertising since 1931 and proof that our jolly fat man was there before Coke co-opted him, go to the Urban Legends Internet site at http://188.8.131.52/cokelore/santa.htm. There you will find the American history of Santa, his reindeer -- the standard 8 plus Rudolph -- the sleigh, toyshop at the North Pole, etc. A site with a little more Santa history and links to other Christmas stuff is at http://www.veeeness.com/MerryChristmas/santaclaus.htm. For a site with capsule descriptions of some international Santas, including Italy's Babbo Natale (who in some households is edging out the Befana) there is http://www.thegrid.net/dicktibbetts/intl_santas.htm. These and dozens of other easily found Internet sites demonstrate that Santa Claus is really a composite of many gift-givers.
The name of Santa Claus is generally acknowledged to be a corruption of the name of Saint Nicholas, who was bishop of Myra in Lycia (modern Demre, near Antalya on Turkey's southern Mediterranean coast) and died in the middle of the 4th century AD. Not much else is really known about Saint Nicholas, but legends started to accumulate around him shortly after his death and entombment in his church in Myra. The cult spread, and in the sixth century a big church was built in his honor in Constantinople. One of the legends attached to his name is that he anonymously provided dowries for three impoverished sisters. Other Saint Nicholas legends are available at http://saints.catholic.org/saints/nicholas.html.
Everything was fine for a while, and miracles ascribed to Nicholas occurred regularly at his tomb in Myra. The Saint was highly honored in the eastern Mediterranean and in areas where Orthodox Christianity took root. And then something unusual happened. Islamic Saracens had conquered Myra, like the rest of Turkey, and this provided an excuse for theft of the relics of Saint Nicholas. Both Venice and Bari were plotting, but it was Italian merchants from the latter city who actually stole the Saint's body from Myra in 1087 and took it by sea to Bari, where a new Church was built to house the relics. This action is now known as the "holy abduction", and it is only one of several "translations" or movements of relics that occurred under similar circumstances at about that time. A contemporary account of the "translation" of Saint Nicholas is at http://www.fordham.edu/halsall/basis/nicholas-bari.html.
The Saint Nicholas's remains are still there in San Nicola and are said to have miraculous healing powers. Since the collapse of communism, large numbers of pilgrims from Russia, where veneration of Saint Nicholas has always been extremely popular, have visited the San Nicola church in Bari. (The church, by the by, is very unusual: it was the first ever Roman Catholic church to house a dedicated chapel where Orthodox Christians hold their liturgy. The English part of an Internet site for the Church of San Nicola in Bari is at http://www.op.org/san-nicola/basilica/pilgrims.htm.) The Catholic and Orthodox churches believe that Nicholas offers special protection to merchants, mariners, prisoners, travelers, bakers, and, of course, all children. The feast of Saint Nicholas is on December 6, and that is when he is said to deliver his gifts in many countries.