Ancient historical sources confirm the main moments of the winter holiday, the return of the sun, which are found in the 20th century Lithuanian beliefs and traditions.

Supper on Christmas Eve " Kūčios", the oldest Lithuanian feast, celebrated according to the sun's calendar. It is a night holiday, whose festivities begin in the evening. This is not only the most archaic, but the best preserved of holidays. Intimate family celebration, in closed micro social environment, protected " Kūčios" from many 20th century modern innovations. The pagan spirit of Lithuanian "Kūčios" did not confront with Christian humanistic philosophy.

"Kūčios" is the ritual supper. The entire December 24th day , Christmas eve is called "Kūčios". "Kūčia" is a special dish assigned to the souls of dead ancestors. It is made of stewed wheat, peas, beans, sweetened with honey or eaten with poppy seed milk. The ritual supper is not eaten until the evening star appears in the sky. Until then, the bathhouse is heated, people bathe and dress up in festive clothes. The floor was strewn with juniper by the mistress and the master placed handfuls of hay on the table, covered it with a white linen tablecloth. In many regions, a basket filled with hay, sheaves of grain and a horse's collar was placed under the table. Foods were placed on the table and as many tablespoons as there were eaters. If the number of family members was an odd number, a beggar or a lone neighbor was invited. If during that year there had been a death in the family, an upside down spoon was set in that place. This being a family feast, not only live but also dead members participate in it. The eldest family member went outside to invite the souls of the ancestors, the cold, the wind and bees to eat together.

The tradition of feeding the souls of the dead, remain in the 20th century in many parts of Lithuania. Most often the "Kūčia" table was not cleared away, for it was believed that when the family is asleep the souls of the dead come in to eat.

Christmas biscuits [ kūčiukai ], are among ritual foods together with barley porridge, both eaten with poppy seed milk. Ancient "Kūčia" supper dishes are beet soup with mushrooms, and fish. Twelve different dishes were prepared, this tradition still continues. All dishes are meatless, with no fat, eggs and dairy products. Today's "Kūčia" supper is begun with the passing around of the Christmas wafer together with wishes for each member.

Lithuanian "Kūčia" traditions have much room for concern about upcoming grain harvest. At the end of the meal it is tradition to pull a piece of hay from under the tablecloth. If one pulls the longest piece, the linen will grow best.
On Christmas Eve a greater attention was given to animals, their health, fertility and assure cattle breeding success: Hay from the supper was later fed to the animals. All throughout Lithuania until this day there is belief that at midnight on Christmas Eve day animals speak. Exactly at midnight, animals rise, kneel on front legs and pray in human voices. Their spoken words are not heard by everyone. The animal voices are heard by those who are poverty stricken and who are spending the night in the barn.
The mirror, invented in the third millenium before Christ, reached Lithuania in the 13th century. Its mysteriousness is linked with the world of the dead, it became part of Christmas Eve enchantings, guessing the future, especially that of marriage. Young men and women, wishing to find out who will be their mate, when casting lots take two candles, a towel and a mirror to an uninhabited house. The candles are lit and placed near the mirror. Wiping moisture from the mirror with the towel, they would see their future mate. Worthy of attention in magic rituals' execution is total nudity. After supper, the girl should climb up into the attic, undress and walk three times around the chimney, then in total darkness she will see the young man she will marry. It is said that one should run to the bathhouse, undress and stand totally naked on the doorstep, bend to look into the stove's opening – there she'll see her future husband. Total belief belongs to magic spiritual rituals, when the girl takes her hair and burns them while speaking the name of her supposed male. If that man lives near by, then he comes around the same night. If he lives farther away, he comes in the morning, and asks who was calling him. The future mate can be seen after collecting crumbs from all Christmas Eve supper foods and burning them in the entry way in a fire lit with remaining Advent splinters. A man's facial features can be seen in the rising smoke.
Christians began celebrating Christ's birth on December 25th , according to the civilian Roman calendar. Ethnographers maintain that Christmas is an ancestral holiday. It is sun and nature Gods' birthday. Lithuanian Christmas rites have much in common with the rites of other Indo European nations.

On Christmas morning, the Christmas Eve supper table was cleared away and checked to see if souls of the dead left any signs of having been at the table.

Pork or wild boar meats were ancient traditional Christmas foods. Later written sources mention ritual pork meat dishes eaten during spring festivals and the start of agrarian labors. Tradition of slaughtering pigs before Christmas was widespread throughout Lithuania. Pig's head, decorated with greenery, was the main Christmas dish. In Samogitia the traditional ritual food is hodgepodge with pig's tail sticking out of the serving dish. This was prepared by that member of the family who stayed home to look after the property while other members attended midnight mass.

Christmas merry making usually began on the second day of Christmas or on the eve of the first day of Christmas and continued until Epiphany, the feast of the Three Kings. Youth groups called alms collectors, darlings, gypsies or by other names, walked through villages under the pretext of wishing good harvests while greeting all homeowners. They received gifts for their greetings. Each group's leader had the duty to request permission to enter homes only when invited. In the Highlands, the youth group was collected by Santa Claus, saying to each of them, " I will lead the lambs". Each youth clung to Santa's coat and soon a flock of lambs was collected. Santa was a popular Christmas wanderer, dressed in an inside out fur coat, humpbacked, carrying a crooked cane and a bag to hold gifts. Santa knocked on doors with his cane. When asked who is knocking, he would answer, "this is Santa, I came from the other land, where there are hills of flour, rivers of honey, lakes of beer, rains in candy, snows in bagels. I carry a bag filled with luck, harvest and other goodies. Please open the door and don't chase me away to the other land". Once inside the house, Santa gave nuts to the children, sang and danced with them. In seacoast villages, Santa was replaced by a night watchman who walked near every house, singing Christmas hymns and wishing success to everyone. He was awarded delicious foods for all his doings.

At the end of 19th century, in villages throughout Lithuania, Christmas celebrations lasted three and four days under the pretext that ice would not destroy the grain fields. During the time between Christmas and Epiphany certain works were allowed while others were not. Almost no work was done after sunset and on holiday evenings: no spinning and no grinding. Only feather tearing could be done.