New Year's Day Calendrical History
In order to understand how the Western world came to celebrate the New Year on January 1, it may be useful to summarize the calendrical history of this date with some basic facts about the lunar and solar calendars of the Sumerians, Egyptians, Hebrews, Greeks, and Romans.
The adoption of the solar year as the unit of time is of Egyptian origin. The majority of other historical cultures, like those of Sumer—and Egypt itself down to a certain period—had a year, at once lunar and solar, of 360 days (12 months of approximately 30 days each), to which five intercalary days were added. The Sumerians of Babylon were probably the first people to make a calendar. They used the phases of the moon, counting 12 lunar months as a year. To make up for the difference between this year and the year of the seasons, they inserted an extra month in the calendar about every four years. For the Sumerians, the Years consisted of twelve lunar months of 29 or 30 days. To keep the lunar year (354 days) in step with the solar year, the king decreed the addition of an intercalary or extra month to the Sumerian calendar every three years or so. The year began after harvest time, in September/October. Later, the Babylonians moved the start of the calendar year to spring. The lunar calendar was synchronized with the solar year, the seasons, by intercalation of a leap month every few years.
The early Egyptians, Greeks, and Semitic peoples copied this calendar. Later the Egyptians worked out a calendar that corresponded almost exactly to the seasons. The early Romans also used a calendar based on the moon. The year in this calendar was 355 days long. The months corresponding to March, May, July, and October each had 31 days; February had 28 days; and the rest had 29. An extra month was added about every fourth year. Thus the New Year was celebrated around the Vernal Equinox, depending on the synchronization of the lunar and solar calendars. The New Year and month would begin on the first New Moon, after the completion of the old lunar year. The day began and ended at sunset and contained twelve hours.
After the Babylonians, the Romans continued to observe the New Year in late March, but their calendar was continually tampered with by various emperors, so that the calendar soon became out of synchronization with the sun. In order to set the calendar right, the Roman senate, in 153 BCE, declared January 1 to be the beginning of the New Year. This calendric tampering continued until Julius Caesar, in 45 BCE, reformed the traditional Roman calendar (with help from an Alexandrian astronomer) and established what has come to be known as the Julian calendar. Following the solar year, the new calendar calculated a year to be 365 and ¼ days long. That year, 45 BCE, Caesar added 67 days so that the New Year would begin on January 1. However, it again established January 1 as the New Year. But in order to synchronize the calendar with the sun, Caesar had to let the previous year drag on for 445 days.
In the Middle Ages, when it was discovered that Caesar made a slight mistake in the calendar calculation, many stopped following the Julian calendar. (The Julian calendar, which had already been in use for a millennium, was based on a 365 ¼-day solar year, with a day added every four years. Over the years, the calendar slipped out of sync with the seasons.) In the 1570s, Pope Gregory XIII commissioned a Jesuit astronomer to fix the 11-minute mistake. Thus, in 1582 AD, Pope Gregory XIII issued a papal bull, introducing the Gregorian calendar. The Gregorian calendar's only real change was that there would be no leap year on century years not exactly divisible by 400. The new calendar took effect in most Catholic countries some eight months later, when the calendar went from October 15 to October 4, 1582. Since then, Jan. 1 has become widely accepted as the New Year in the Western world.
The beginning of the year varied from country to country as well as in different periods, calendar reforms being constantly introduced to make the ritual meaning of festivals fit the seasons with which it was supposed to correspond. However, neither the instability and latitude in the beginning of the New Year (March‑April, July 19, as in ancient Egypt, or September, October, December‑January, etc.) nor the different lengths attributed to the year by different peoples were able to lessen the importance attached, in all countries, to the end of a period of time and the beginning of a new period.