Ah, the yearly Zwarte Piet (Black Peter) question: very tiresome to explain it every year, but we will go to the effort to copy and paste an explanation from dutchmarket.com (below), which anyone can find, along with many others, if one makes the slightest effort.
Pepermoten are the little ginger cookies handed out by Zwarte Piet. The name of the band full of Zwarte Pieten comes from that. Sunday was the day Sinterklaas makes his arrival in Holland---the parade starts at Centraal Station, where he arrives by boat from "Spain", and proceeds throughout the city to de Dam. We actually saw the parade earlier in the day near Leidseplein, and our pockets are still full of all the cookies we received from various Zwarte Pieten--- which are today played by both sexes. Sometimes, depending upon by whom he is being played, he'll be portrayed as a jokester (as said below), but very often he be a bit scary---the guy who'll throw you in his sack if you weren't a good boy or girl. And we weren't. So we be a scared ;-)
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Did you know that it was Dutch Immigrants who brought the tradition of Santa Claus to the rest of the world? That's right! It all started waaaay back in the 4th Century when a Bishop in Turkey named St. Nicholas became widely known for his good deed with poor children in Europe. His feast day became known as the Celebration of Sinterklaas and was held on December 6. St. Nicholas is also known as the patron saint of Amsterdam. Many different versions of the story of Saint Nicholas are told but there are some common characters in each one. First is Saint Nick's companion Zwarte Piet. Some believe that Zwarte Piet was a black slave. This is not the case. Zwarte Piet is said to be a Turkish orphan that traveled as St. Nicholas' helper. His darker Turkish features must have seemed black to the fairer 4th Century Dutch. The second common character is Schimmel, St. Nicholas' fine white horse.
St. Nicholas is pictured in medieval and renaissance paintings as a tall, dignified man dressed in red vestments carrying a Bishop's golden crook. Zwarte Piet is depicted in garish Turkish garb with bright red lips and a gold earring. The legend describes St. Nicholas and Zwarte Piet traveling from their home in Spain across Europe helping the poor and bring food to children. Through the ages, the story of St. Nicholas astride his white horse with this helper Zwarte Piet grew into a tradition to celebrate the feast day on December 6th. St. Nicholas travels to Holland on a steam ship from Spain. He would leave in mid November and arrive on December 5th. Just in time to place small gifts and treats like pepernoten, chocolate initials, marzipan figures and fruit.In the past, St. Nicholas carried a Birch switch used to punish children who were naughty and Zwarte Piet was said to put bad children in his sack or would leave them a lump of coal in their shoes instead of treats. Today, St. Nicholas is portrayed as a more gentle figure and Zwarte Piet is a jokester.
Another version of the story is available at Expatica:
http://www.expatica.com/source/site_art ... iet+debate