Thursday, December 6 is Saint Nicholas Day, the feast day of the Christian bishop who lived during the fourth century in what is now Turkey, and whose name we associate so much with chimneys and stockings hung with care.

There is an old story about Nicholas and his remarkable generosity. When he was a young man living in his hometown of Patara, he heard of a family that had fallen on hard times. The desperate parents were too poor to provide dowries so that their three daughters could marry. They decided that the only way to keep their daughters from starving was to sell them into servitude.

Nicholas put a few gold coins he had inherited into a small bag and, one night when the family was sleeping, tossed it through a window into their home. It was enough money to provide a dowry for the oldest daughter, who was soon married.

When Nicholas saw the effects of his gift, he returned and tossed another bag of gold through the window so the second daughter could be married. When he came several nights later with a third bag, the tearful father was waiting to see who their secret benefactor was. Nicholas begged him not to tell anyone, but his act of generosity set him on the path to becoming the world’s most famous gift giver.

Such are the stories of Nicholas that have come down to us. His life, to be sure, is obscured by time and legend. It’s a history I explore in my book, “The True Saint Nicholas.”

Nicholas was a man of God who worked tirelessly for his flock. But the most remarkable part of his story comes after his death. People began to tell stories about the bishop and his power to change people’s hearts. Because all the good he did was a kind of miracle, they told stories of the miraculous — stories of a man who could accomplish things no ordinary person could.

“It is easier to count the waves of the sea, the drops of rain, the stars, and with a glance see all the Atlantic than to recount in detail God’s marvels accomplished through Saint Nicholas,” an eighth-century hymn proclaimed.

Nicholas gradually became an international phenomenon in the Old World. By the end of the fifteenth century, more than 2,500 churches, monasteries, hospitals, schools, and works of art had been dedicated to him in Western Europe.

At some point in the Middle Ages, people began exchanging gifts on December 6, Saint Nicholas Day, perhaps in memory of the bishop’s generosity. In some places, children woke to find their shoes filled with fruit or nuts — gifts from the kind old saint.

We live in a time of social turmoil and drama. Nicholas’s standing endured such a time during the Reformation when Protestants turned against traditions surrounding the saints. The most zealous reformers took hammers to sculptures of Nicholas and other saints. They smashed stained-glass windows depicting their deeds. Pages containing lives of the saints were used to polish boots or wrap fish.

Nicholas was driven from many churches, but he could not be driven from people’s hearts. Over the centuries, something extraordinary happened. He moved into homes and became a hero of the hearth.

In America, of course, he transformed into the champion bringer of gifts. Those three bags of gold have become Santa’s sack of toys.

Yes, Santa Claus (whose name comes from Sinterklass, the Dutch name for Saint Nicholas) is sometimes overexposed and exploited. At his best, though, he stands for the virtues that Saint Nicholas championed: generosity, selflessness, largeness of spirit.

There is one essential truth in the stories of Nicholas and Santa Claus: the goodness of the gift offered with no expectation of anything in return. That spirit lives in any parent who with secret joy watches a wonder-struck child on Christmas morning.

The legacy of Saint Nicholas has rippled across 17 centuries, bringing messages of faith and joy. His is a story worth knowing, especially this time of year.