Saint Nicholas Day, also called the Feast of Saint Nicholas, observed on 5 December or on 6 December in Western Christian countries, and on 19 December in Eastern Christian countries using the old church Calendar, is the feast day of Saint Nicholas of Myra; it falls within the season of Advent. It is celebrated as a Christian festival with particular regard to Saint Nicholas' reputation as a bringer of gifts, as well as through the attendance of church services.
In the European countries of Germany and Poland, boys have traditionally dressed as bishops and begged alms for the poor. In Poland and 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. In the Netherlands, Dutch children put out a shoe filled with hay and a carrot for Saint Nicholas' horse. On Saint Nicholas Day, gifts are tagged with personal humorous rhymes written by the sender. In the United States, one custom associated with Saint Nicholas Day is children leaving their shoes in the foyer on Saint Nicholas Eve in hope that Saint Nicholas will place some coins on the soles.
The American Santa Claus, as well as the British Father Christmas, derive from Saint Nicholas. "Santa Claus" is itself derived in part from the Dutch Sinterklaas, the saint's name in that language. However, the gift giving associated with these descendant figures is associated with Christmas Day rather than Saint Nicholas Day itself.
5/6 December (Western Christianity and Eastern Christianity on the New Calendar);
19 December (Eastern Christianity on the Old Calendar)