St. Nicholas was a Bishop who lived in the 4th century in Myra, Asia Minor (now Turkey). He was a very rich man because his parents died when he was young and left him a lot of money. He was also a very kind man and had a reputation for helping the poor and giving secret gifts to people who needed them. The stories may or might not be true.

There was a poor man who had three daughters. He was so poor, he did not have enough money for a dowry, so his daughters couldn't get married. One night, Nicholas secretly dropped a bag of gold down the chimney and into the house. This meant that the oldest daughter was then able to be married.The bag fell into a stocking that had been hung by the fire to dry! This was repeated later with the second daughter. Finally, determined to discover the person who had given him the money, the father secretly hid by the fire every evening until he caught Nicholas dropping in a bag of gold. Nicholas begged the man to not tell anyone what he had done, because he did not want to bring attention to himself. But soon the news got out and when anyone received a secret gift, it was thought that maybe it was from Nicholas.

St. Nicholas putting the bag of gold into a stocking is probably where the custom of having a tangerine or satsuma at the bottom of your Christmas stocking came from. If people couldn't afford gold, some golden fruit was a good replacement - and until the last 50 years these were quite unusual fruits and still so special!

More Info: en.m.wikipedia.org