We're all vaguely aware that Santa Claus and St. Nicholas are essentially one and the same figure.
St. Nicholas' feast day is this coming Sunday, December 6. Across the Atlantic on Saturday night, in the Netherlands, in Belgium, in Germany, in Poland, and in parts of France, especially eastern France,* children will put their shoes next to the fireplace or door and fill them with carrots, hay and grain. The next morning, their shoes will be filled with treats of candy, coins, and other goodies, like oranges.
They are leaving the carrots and hay for St. Nicholas's horse. In Central Europe, St. Nick doesn't have a sleigh with eight tiny reindeer--he rides a white horse! In recent years, in the Netherlands in particular, this horse has been called Amerigo or Schimmel.
St. Nicholas of Myra (270 -246) was a bishop from Turkey. He is associated with gift giving and children because of two of the stories associated with his sainthood. One involves his giving of dowries to three sisters so that they could escape lives of prostitution. The other involves his resurrection of three children who were murdered by a butcher and hidden away in a salt tub.
Like many modern traditions, traditions surrounding St. Nicholas and Santa Clause have their origins in pagan traditions. Odin, the Norse god, rode an eight-legged flying horse, Sleipnir. In some places, in the winter, offerings were made to Sleipnir in the form of carrots and hay left by the door or chimney, in order to curry favor with Odin. This is the origin of the Feast of St. Nicholas tradtion of leaving gifts for Amerigo (or for Santa's reindeer). Likewise, Sleipnir's eight legs and magical powers may well have been the origin for Santa's EIGHT flying reindeer.