St. Nicholas is the patron of children. According to one legend, he supplied three destitute maidens with dowries by secretly leaving a marriage-portion for each at their window. This started the legend of him being a purveyor of presents to children on Christmas Eve.
He usually makes his appearance as an old man with a venerable beard and dressed as a bishop, either riding a white horse or an ass and carrying a large basket on his arm and a bundle of rods in his hand.
Other areas of Bohemia may have seen him dressed in a sheet instead of a surplice and wish a crushed pillow on his head instead of the traditional ceremonial head gear.
Other names St. Nicholas is known by in European countries is Samiklaus of Switzerland and Sonner Klas of Helgoland. He is also been known as Zemmiklas, Niklo, Sunder Klaas, Sinterklaas, Santa Claus and also Holy Man.
In many parts of Switzerland, Germany and the Netherlands St. Nicholas still distributes his present on St. Nicholas's Eve* -- the 5th of December -- instead of the Christmas Eve.
One custom is for children polish their shoes and fill them with hay and oats for St. Nicholas' white horse, the next morning the shoes are hopefully filled with sweets and toys for the good children and rods for the bad ones.
In several regions of Europe different "bugbears" have accompanied St. Nicholas as a way of frightening the children and keeping them in line. Krampus, Knecht Ruprecht, Klaubauf, Hans Trapp and Zwarte Piet are just a few of the scary ones, although Zwarte Piet isn't really a frightening creature.
The one recurring theme throughout most of the stories of St. Nicholas is how he has saved the children, maidens and even sailors from harm, at times even restoring them to life. But woe to the child who has not been good -- for he does remember and his mean sidekick will punish with twigs, possibly carry them off and of course, no sweets.
*St. Nicholas died on December 6, 343 (year is disputed) and the anniversary of his death has become St. Nicholas Day.