A twelve-dish Christmas Eve supper is traditionally prepared to commemorate Jesus' twelve disciples in Central, Northern and Eastern European cultures, especially those that were formerly part of the Polish–Lithuanian Commonwealth and neighbouring countries. The tradition is especially cultivated in modern-day Poland, where alternatively thirteen meatless dishes on Christmas Eve are sometimes served. Description The specific dishes may differ from country to country, but many of them are universal. Due to the Nativity Fast, no meat, eggs or milk (including cheese) are allowed during the supper. Thus fish, mushrooms and various types of grain are the main offerings. In Poland, the Wigilia supper begins with eating soups, traditionally mushroom soup or barszcz. The ritual for Catholics and Orthodox Christians in Ukraine is to start with kutia. Kutia, poppy milk (aguonų pienas) together with kūčiukai are served as a dessert and forms a significant part of the Lithuanian Christmas Eve menu. Poppy seeds are widely used for Christmas Eve dishes, because they symbolise abundance and prosperity. In Poland, it was traditionally believed that the poppy seeds, known for their sleep-inducing power, may have been helpful on the way to the afterlife or as a delicacy for souls who come to earth. Honey, a product produced by bees, which are considered by many to be sacred creatures, was offered as a gift to departed souls. In Ukraine, it was believed that varenyky, which are also a symbol of prosperity, with poppy-seed filling when served at Ukrainian Sviata Vecheria have the most magical potential for bringing prosperity and fecundity to the villager. Regarding the fish dishes, these are usually herring, carp or pike. In Lithuania, herring () dishes are popular and diverse. Usually silkė su morkomis (herring with carrots), or silkė su grybais (herring with mushrooms) are served on Christmas Eve. Mushrooms, especially dried or pickled, are also one of the main ingredients used in Christmas Eve dishes. Sauerkraut (Polish: kiszona kapusta, Ukrainian: кисла капуста; kisla kapústa) with wild mushrooms or peas, red borscht, mushroom or fish soups are served in Poland and western Ukraine. Boiled or deep fried dumplings (Polish: pierogi, Ukrainian: вареники, varenyky, Lithuanian: auselės) with a wide variety of fillings (including cabbage or sauerkraut, mushrooms and crushed poppy seeds), are among the most popular dishes. Doughnuts filled with jam (Polish: pączki, Ukrainian: пампушки, pampushky) are served for dessert in Poland and western Ukraine, but in Lithuania sweet dishes are not common,