Saint Nicholas' Day, observed on December 6 in Western Christian countries, December 5 in the Netherlands and December 19 in Eastern Christian countries, is the feast day of Saint Nicholas.
It is celebrated as a Christian festival with particular regard to his reputation as a bringer of gifts, as well as through the attendance of Mass or worship services. In Europe, especially in "Germany and Poland, boys would dress as bishops begging alms for the poor."
In Ukraine, children wait for St. Nicholas to come and to put a present under their pillows provided that the children were good during the year. Children who behaved badly may expect to find a twig or a piece of coal under their pillows.