Lithuanians always felt a close relationship to nature, its influence on them and its cyclic recurrence. All farm work was done at the same time every year. The main reference points of the national calendar are determined by beginning and end of all work, spring and autumn, winter and summer solstice.A calendar is a summarizing regulation of practical activity, work distribution and sequence. The beginning and ending of a larger, more important job was designated by a festival. Festivals were a form of rest after heavy, daily toil, a time of concentration and preparation for other labors. During these festivals, inherited ancestral traditions of rebirth of nature, earth awakening, ancestor commemoration were maintained. One of them is a belief that the souls of the dead return home to their family during these annual holidays. That is why people waited and prepared for them. Everything in the house was cleaned, everyone bathed and dressed in holiday garb. Women prepared traditional foods that their mothers and grandmothers used to. 
Improper preparations for the festival or shortage of help to the souls of the dead, would bring out the souls' wrath. Angry ancestors could harm the fields, crop capacity, animals' fertility and peoples' health. For these reasons people sought the dead souls' benevolence. The dead were still considered members of the family and while partaking of food together would accede to common family problems. The holiday foods prepared from the year's harvest, predetermined a good harvest, fertility, good health and success for everyone. The tradition to distribute left over food to beggars continued, for it was believed that they have a mysterious relationship with the dead, they are the go- betweens between the living and the dead. It was imperative to share food with them for the same purposes good harvest, health and peace for the dead. 
On the basis of calendar festivals, Lithuanians created rich ceremonies and myths connected with the cults of earth, water, wind, sun, moon, stars, etc., the meaning of which was embodied by goddesses and mythical beings.
Renewal of time and beginning of new year, Lithuanians linked traditionally with the return of the sun. These festivals began around December 20-24 and ended after two weeks, when the days were longer by a rooster's step. The celebration of New Year on January 1 was begun in the 19th century. Christianity came to Lithuania in the year 1387 and Lithuanians accepted the Christian rituals and new feast days distrustfully. When the country became totally Christian, Lithuanians continued their inherited, ancestral celebrations. The ancient and new Christian rituals took several centuries to combine. At the end of the 19th century and even in the first decades of the 20th century, holidays had double names, ancient and Christian. Some of them have remained till now. For example, the 24th of June, the feast of St. John the Dews [ a.k.a. Rasos ], the 15th of August, Virgin Mary's going to heaven Herbal Holiday [ a.k.a. Þolinë ], 8th of September, Virgin Mary's birthday Pine Forest Holiday [ a.k.a.Ðilinë ] and so on. 
The Moon calendar was used in ancient Lithuania. The Sun calendar took root with the development of agriculture. From the middle of the 13th century, till the end of the 16th century, the Julian calendar became official in the Grand Duchy of Lithuania. The Gregorian calendar was introduced in the year 1586. This counting of time was abolished in 1800 when Lithuania was divided for the last time and fell under Russian rule. Russia used the old Julian calendar and reintroduced it in Lithuania. In 1918, when Lithuania became independent, Lithuanians began to use the new countings of time. Changes of official calendars caused many disorders and misunderstandings in calendar traditions. 
The names of months in Lithuania are connected with phenomena in nature, seasonal works, holidays, flora and fauna. The days of the week are called according to their place in the week;
Pirmadienis, first day, Antradienis, second day, Treèiadienis, third day, Ketvirtadienis, fourth day, Penktadienis, fifth day, Ðeðtadienis, sixth day, Sekmadienis, seventh day. 
Traditions and ceremonies of calendar holidays were constantly in the flow of centuries. Some disappeared, others changed beyond recognition, new ones appeared. All these processes occurred slowly and imperceptibly.