Every region has its own tradition. In some regions of Poland the gifts are given to the children only on December 6th - since St. Nicolaus called also Santa Claus is a patron of this day. Read more about St. Nicolaus tradition. But in the majority of houses children (and adults) can expect gifts twice- on December 6th and also on Christmas Eve. As you probably know St. Claus Day originates from orthodox religious tradition but it came to Poland probably from Holland. The atmosphere of this feast is different than the atmosphere of Christmas eve since December 6th is a normal working day. Whereas Christmas is usually celebrated as a family feast, St. Claus Day (December 6th) is rather social - with children and adults participating in Christmas parties at schools and offices.
In the beginning of XX century the Santa was accompanied by angels and the old man (dziad) who was caring a big sack full of gifts. Later the old man was replaced by a devil. So the "rich" santa, who can afford the company, is accompanied by the angel and devil - the devil is punishing the kids whereas the angel is praising them and Santa is distributing gifts among them.
Since Santa brings souvenirs two weeks before Christmas usually other God's helpers are responsible for bringing gifts during Christmas Eve (December 23). For instance in the region of Great Poland (Wielkopolska) which encompasses Poznan (Posen) and the area of West-Central Poland, the Starman = a man with a star (Polish: gwiazdor) brings the gifts to the children. Starman is not that jovial and kind as Santa Claus, he is first threatening children with the beating wooden birch (Polish equivalent of cane), but later he is opening a sack with presents. The tradition of a starman is a very old indeed. It is even older that a tradition of Santa Claus. Starman came to Poland probably from Germany where it was called a Weihnachtsman (Christmas man). Since protestants do not celebrate a tradition of saints - the Weihnachtsman could be secularized originally from St. Joseph, Jesus's father and protector. The ritual of a starman may originate also from the traditions of carolers - boys or young men walking from home to home and singing carols or from a figure of so called wigiliarz from the word wigilia meaning Christmas eve. Wigiliarz wore a military cap with many embellishments, similar to starman.
In the Little Poland and in Silesia baby Jesus or his messenger, a small angel (Polish: aniolek) are bringing souvenirs to kids during Christmas eve. Baby Jesus and a small angel are invisible, their presence is only signalized by a ringing of the bell, the moment later - the presents are available to see.
The communists tried to eliminate any religious connotations so Christmas. If they would succeed (luckily they did not) we would have to celebrate Grandfather Frost (Russian: Dyadya Moroz) and he would be bringing the souvenirs to kids on the New Year's Eve.
Extensive selection of Polish carols is at: http://culture.polishsite.us/articles/art125.html
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