How Many Jewish New Years?
In ancient times there were four new years on the Jewish calendar.
Time, in its essence, is an unceasing flow on which human beings have imposed meaning with arbitrary divisions and markers--years, months, weeks, days, minutes, and seconds. These units of time serve as measures for human activity in education, commerce, leisure, agriculture, and religion.
Jewish time grew out of God's imposition of order on the primeval chaos. First, God separated the light from darkness, creating day and night. Then, as a reflection of God's cycle of creation and rest, the work week was differentiated from Shabbat. Later, at the time of the Exodus, God mandated that the Israelites mark the new moon of Nisan, thereby establishing a monthly and yearly cycle.
As the body of Jewish law developed, the Jewish calendar has served to demarcate both holiday observances and numerous time-bound obligations. To ensure that certain commandments were completed at their appointed times, four different Jewish new years were established to provide boundaries and markers for these activities. For example, since the Israelites were required to contribute a tenth of the current year's produce, they had to know exactly when the current agricultural year began and ended.
The four Jewish new years specified in Mishnah Rosh Hashanah 1:1 are 1 Tishri, 15 Shevat, 1 Nisan, and 1 Elul.
The first of Tishrei serves as the New Year for several purposes, the best known being the New Year for the civil calendar, or "the new year for seasons." Rosh Hashanah literally means "the head of the year." Jewish years are traditionally figured from creation (for example, this year is considered the 5763rd year from creation), with the New Year beginning on 1 Tishrei. Although Rosh Hashanah is not a well-defined holiday in the Torah, distinguished mostly as "a day when the horn is sounded" (Leviticus 29:1), the Talmud expanded its religious connotations to make it the Jewish New Year and the anniversary of creation. Rosh Hashanah 8a explains, "For R. Zeira said [that Tishrei is considered the New Year for years in relation] to the seasons. And this [opinion of R. Zeira] is [in consonance with the view of] R. Eliezer, who said that the world was created in Tishrei." In fact, the rabbis focused particularly on the creation of human beings, without whose perceptive ability the physical creation would go unappreciated.
As the beginning of the civil calendar, 1 Tishrei is also considered the new year for measuring the reigns of foreign kings, necessary because legal documents were dated by the current year of a monarch's reign. Rather than measuring a king's reign from the date he took office, 1 Tishrei served as a standard anniversary marking the end of a full year of rule, even if that "year" had only been part of a year.