When is St Nicholas Day? And how did this Christian saint inspire the Santa Claus legend?

The white-bearded Christian saint whose acts of generosity inspired America's secular Santa Claus figure is known worldwide - but Saint Nicholas' origin story is not.

The legends surrounding jolly old St Nicholas - celebrated annually on December 6 - go way beyond delivering candy and toys to children.

WHO WAS ST NICHOLAS?

St Nicholas was a fourth century Christian bishop from the Mediterranean port city of Myra (in modern-day Turkey).

"Much of the rest is legend. There's not really a lot of hard historical evidence about St Nicholas," said the Rev Nicholas Ayo, author of "Saint Nicholas in America: Christmas Holy Day and Holiday."

But whether the stories are true is not so much the point, said Ayo, an 89-year-old retired Notre Dame University professor named after St Nicholas.

"There's no Santa Claus that lands on the roof...