Saint Nicholas was a bishop of Myra, in Asia minor, in the forth century. Lots of stories are told of his kindness and generosity. he is the patron saint of Russia, Children, Scholars, merchants and sailors.
One legend tells of his secret gifts to 3 daughters from a poor family. It is said that he threw 3 purses of gold down the chimney where they landed in the girls stockings which had been hung up to dry in front of the fire. This is supposed to be the origin of hanging up Christmas stockings.
Over time the name Saint Nicholas changed to Sinterklass and thus Santa Clause in the Christmas celebrations.