St. Nicholas was a real, live PRIEST in the 4th century AD. He had quite a bit of Money, and was know for giving gifts to children in his town.
As God gave the Gift of Jesus to mankind to forgive us all of our sins so that we, each and every one, night go to heaven, the idea of giving gifts is intertwined with the idea of Christmas.
tyhe diea of a fat man in a red suit did not come about until much later, someitme int eh alte 19th century. He appeard on advertising around 1900, but Coca Cola made teh fat Man int ehj red Suit popular through theri advertsiing, as eal;y as 1930.