
From Wikipedia:
In the folklore and legends of the Netherlands and Belgium, Zwarte Piet (About this sound pronunciation (help·info)) (meaning Black Pete) is a companion of Saint Nicholas (Dutch: Sinterklaas) whose yearly feast in the Netherlands is usually celebrated on the evening of the 5th of December (Sinterklaas-avond, that is St. Nicolas Eve) and the 6th of December in Belgium, when they distribute sweets and presents to all good children.
Some sources indicate that in Germanic Europe, Zwarte Piet originally was such an enslaved devil forced to assist his captor, but the character emerged in the 19th century within the Netherlands as a companion of Saint Nicholas resembling a Moor.[1] Saint Nicholas is said to come from Turkey. The relation of Zwarte Piet with Haji Firuz is incredibly close, Haji Firuz is a traditional herald of Nowruz, the Persian New Year celebration, exactly black in the face and comes with Amoo Nowruz a white beared old man who brings gifts for the children counter part of Western Santa.
The introduction of this new Zwarte Piet was paired with a change in the attitude of the Sinterklaas character that was often shown as being quite rough against bad children himself and thought unbefitting of a Bishop by teachers and priests. Soon after the introduction of Zwarte Piet as Sinterklaas’ helper, both characters adapted to a softer character.[2]
Until the second half of the 20th century, Saint Nicholas’ helper was not too bright, in line with the old colonial traditions. Once immigration started from the former colonised countries Zwarte Piet became a much more respected assistant of Saint Nicholas, who is often a bit inattentive.[3]
According to the more modern Saint Nicholas legend, a Zwarte Piet is a servant who accompanies Saint Nicholas on his holiday travels. In some versions, it is alleged that Saint Nicholas once liberated a young slave named Peter, who decided to serve Nicholas (as a free servant) rather than enjoy liberty alone. Zwarte Piet is today commonly depicted as a black person in the colorful pantaloons, feathered cap and ruffles of a Renaissance European page, a tradition based on a single illustration in a book published in 1850.