The following is from my draft Introduction to Folklore, itself drawing on the self-published text (1966) of my mentor Sven Liljeblad (1899-2000). The traditions to which it refers are Northern-European-based:

The preoccupation with time, the division of the day into precisely defined hours, minutes and seconds, and the idea of changing the day at midnight are all modern practices associated with an industrial world. European peasants described time much differently. They separated the day into forenoon and afternoon. Europeans divided the night into watches, of which there were four, accounting for the time it took a night watchman in a town or a large village to make the rounds by walking around the community.

Before industrialization, most languages did not have the concept of a twenty-four hour day, which includes both daylight and night. Words referred either to the time of daylight or night. In modern English, the word “day” is in fact used to include the time of darkness, to which it makes no literal reference. The German word Volltag literally means “full day,” but it is a recent term that suits the need to describe the entire period of time.

For most pre-industrial people, day and night were separate, distinct terms. Time was typically counted in either “days” or “nights” or in “suns” or “sleeps.” Homeric literature counts time with eos, the word for dawn. The English term “fortnight” refers to fourteen nights. Arabic uses a term meaning “three night,” and Sanskrit has a “ten night.”

Referring to a day as the time of daylight made each day longer or shorter according to the time of the year. Each successive forenoon and afternoon, consequently, were different from the previous ones. Traditionally, Europeans regarded the night before the day as being linked to it. Holidays and other days of importance consequently began the ceremony of ritual on the evening before the day. The Jewish Sabbath and holidays begin at sunset for this reason. Similarly Halloween (the evening before Al Hallows Day), Christmas Eve (the evening before Christmas), and New Year’s Eve (the evening before the first day of the year) were originally tied to the day of celebration just as they are today. To the mind of the modern industrial world these evenings anticipate the day of celebration, but they were originally the beginning of the holiday.

The idea of the hour apparently first dates to ancient Sumerian and Babylonian astrologers. They divided the modern twenty-four-hour day into twelve hours. They chose the number twelve to correspond with the twelve months of the year and their corresponding signs of the zodiac. The Romans adopted this system during the first centuries of empire, but it did not take hold entirely. Egyptians contrasted with the Mesopotamian system by using twenty-four hours for the day. Medieval astrologers adopted the Egyptian approach, giving the modern world its system of time keeping. The introduction of the clock and the necessity of precise time keeping in an industrial environment made the hour a strictly-defined unit of time. None of these developments, however, occurred early enough to influence traditional European peasant culture.