CALENDAR. Calendars are devised as a trustworthy means for recording history and determining dates in advance for social, civic, and religious anniversaries, and for economic planning. Comparatively little is known of the calendar of the early Israelites from the patriarchs to the Exile, but a critical study of the biblical records and archaeological discoveries is rewarding.
During the Bible period, time was reckoned solely on astronomical observations. The early Chaldean and Egyptian astrologers became quite learned in the movements of astronomical bodies. Their discoveries, as well as those of other Near Eastern neighbors, made their impact on the Jewish calendar. From earliest times the sun and moon were determinants of periods: days, months, and years.
I. Days in the biblical record of time begin with the account of creation. Various reckonings and measurements were derived from these early records. While the Babylonian day began at sunrise, the Bible reckoned the twenty-four-hour span from sunset to sunset (
Days of the week were not named but were designated by ordinal numbers. The term “sabbath” was not the name of the seventh day but a sacred designation.
Early Hebrews divided the night into three watches: “the morning watch” (
II. Weeks constituted special and significant units of time for the “chosen people.” The seven-day week is of Semitic origin, but reckoned from various reference points. The Babylonians and Assyrians bound their weeks to the lunar cycle, corresponding with the four phases of the moon, and began anew with each new moon. The biblical week had its origin in the seven-day creation account and ran consecutively in a free-week system irrespective of lunar or solar cycles. This was out of the high esteem held for the Sabbath.week had ten days.
Astronomical bodies were divinely ordained in creation to be time markers. Days and years were measured by the sun; months by the moon; and cycles by sun, moon, and stars. The week alone was not controlled by celestial bodies, but originated by divine command for man’s economic, physical, and spiritual welfare.
Though God placed special emphasis on the seventh day at the time of creation (
III. Month, in effect, is a synonym for moon. Apparently all ancient peoples worshiped the moon. They also measured time by it, because of its regular cycles. The Arabic word for moon means “the measurer,” and the Egyptian moon god Thoth was the god of measure. Even apostate Jews at times worshiped the moon along with other heavenly bodies (
“Moon” was synonymous with “month” in common parlance in Moses’ day (
The early Israelites designated their months by names that they borrowed from the Canaanites or Phoenicians. These names had seasonal connotations as implied in the four that have survived in the early biblical records. Abib (
About the end of the kingdom period the calendar was reformed, replacing the old names of the months with ordinal numerals and changing the beginning of the year from fall to spring. This is illustrated in 1 Kings (
The postexilic names of months were, as confirmed by the Talmud, adopted from the Babylonian calendar but not used for civil and historical purposes. These, like the early Canaanite names, had their origin close to nature, as is seen from their derivations. Nisan—“move,” “start,” is the first month of the ecclesiastical year as well as of the vernal equinox. Iyyar—“to be bright,” “flower.” Sivan—“appoint,” “mark.” Tammuz—name of an ancient Akkadian god identified with vegetation. Ab—“hostile” heat, “bulrushes” growing. Elul—“to shout for joy” at vintage. Tishri—“begin” civil year, “dedicate” to the sun-god by Babylonians, and to which the Jews might have associated the Creation and the. Marchesvan—“drop,” “rainy season.” Kislev—derivation uncertain. Tebeth—“to sink,” “dip.” Shebat—also uncertain. Adar—“to be dark.”
The Gezer Calendar, dated in the tenth century b.c., gives an interesting glimpse into the agricultural life in Palestine at that early date. This archaeological find by Macalister is a limestone plaque bearing a Hebrew inscription enumerating farm operations for eight months, mentioning sowing, flax harvest, barley harvest, and vine pruning.
IV. Years. The OT calendar contained two concurrent years: the sacred year, beginning in the spring with the month Nisan, and the civil year, beginning in the fall with Tishri. The sacred year was instituted by Moses following the Exodus and consists of twelve or thirteen lunar months of 29 1/2 days each. The civil year claims a more remote antiquity, reckoning from the Creation, which traditionally took place in autumn (3760 b.c.). It came into popular use in the third century of the Christian era. That this order of the year was kept by the ancient Hebrews is supported by the Mosaic command “Celebrate the Feast of Ingathering at the end of the year, when you gather in your crops from the field” (
The Babylonians and Egyptians devised the intercalary month in order to reconcile the lunar and solar years. The Jewish leap years in their Metonic cycle of nineteen years were fixed, adding an intercalary month to the third, sixth, ninth, eleventh, fourteenth, seventeenth, and nineteenth years. If, on the sixteenth of the month Nisan, the sun had not reached the vernal equinox, the month was declared to be the second Adar and the following one Nisan.
In 46 b.c., a great advance over contemporary calendars was made by Julius Caesar, whose calendar year contained 365 1/4 days. It had a discrepancy of eleven minutes in excess of the solar year, and so was superseded by the in a.d. 1582, which was adopted in England in 1752. It has the infinitesimal error of gaining one day in 325 years.
Josephus (Antiq. 1.3.3) said that Moses ordered that the year of holy days and religious festivals begin with Nisan, the month in which the Exodus transpired, but that he retained the old order of year for buying and selling and secular affairs. This observation has been confirmed by critical study and subsequent Jewish custom of keeping both a sacred and a civil year.
Feasts and fasts were intricately woven into the lunar-solar sacred year. Three great historic feasts were instituted by Moses: “the
Beginning in the month Nisan or Abib (
The Christian Easter, fulfilling the Passover, is reckoned on solar-lunar cycles, coming on the first full moon on or after the vernal equinox (March 21).
The name of the second month, Iyyar, known formerly as Ziv (
Winter holy days were few, though one of significance is mentioned in
Besides the one divinely ordained fast, the Day of Atonement, there were minor fasts, some temporary (
V. Cycles. From God’s hallowing of the seventh day there arose a special sacredness in relation to the number seven. Religious convocations and festivals were highly regarded on the seventh day, seventh week, seventh month, seventh year, and seven times seven years.
Hence, the epitome of the sabbatical feasts, of which the perennial ones have been mentioned, may thus appear. The sabbath of seven days; Pentecost, at the end of seven weeks after Passover; and the Feast of Trumpets, introducing the sacred seventh month, were all “appointed assemblies” (mo’adhim) of the Lord.
The sabbatical year was one of solemn rest for landlords, slaves, beasts of burden, and land, and of freedom for Hebrew slaves. Only what grew of itself on the farm and vineyard was to be gathered and consumed (
The Jubilee, every fiftieth year, following “seven weeks of years,” was a hallowed year whose observance included family reunions, canceled mortgages, and the return of lands to their original owners (
VI. Eras in the Bible calendar constitute the whole span of time from the creation of the world to the consummation of the ages. Great events are terminal markers. These mountain peaks of time, in chronological sequence, are Creation, Flood, Abraham, Exodus, Exile, and Birth of Jesus. Consequently, the eras may be designated Ante-Diluvian, Post-Diluvian, Patriarchal, Israelite, Judean, and Christian. (Cf.
Astronomically, the phenomenal star that guided the Magi divided human history. It is the pivotal point from which all history is dated, terminating the old order and initiating the new. It stands as the signal reference point of all time, the preeminent red-letter date in the Bible calendar. In the Jewish Calendar it separates the history “Before the Common Era” (b.c.e.) from that of the “Common Era” (C.E.). In the Christian calendar it separates all “Before Christ” (b.c.) from that in “ ” (a.d.), “The year of our Lord.”——GBF
Primitive man measured his calendar by the cycle of recurring natural phenomena which he observed, such as the alteration of day and night and the phases of the moon. The calendar in use in NT times was the Julian, based on the Roman republican calendar. By 46 b.c. the republican calendar had grown out of step with the seasons to the extent of three months, and the seasons were no longer in proper relationship with the calendar months. Julius Caesar instituted a four-year cycle, the first three having 365 days and the fourth 366, the additional day being placed in February. The fourth years were known as bissextile years. The modern term “leap year” is derived from the Old Norse hlaupar. In the Julian calendar each year was eleven minutes fifteen seconds too long, a fact which was significant only over a long period. After several delays the new Gregorian calendar was promulgated by in 1582. The leap year rules were altered to deal with the fault in the Julian calendar, and ten days were omitted from 1582 to balance the accumulated error. The calendar is now correct to within one day in 20,000 years. The Gregorian calendar, now used for civil purposes throughout the world, was not generally adopted immediately. Great Britain did not adopt it until 1752, and the Russians did not do so until the rise of the Soviet government in 1917. The Orthodox Church has not adopted it, with the result that its year is now thirteen days behind the Gregorian year. The Gregorian calendar restored New Year's Day to 1 January. Formerly it was 25 March, the supposed anniversary of the Annunciation. The date of Easter is calculated in reference to the epact (the age of the moon at the beginning of the year), and the rules laid down by the are largely adopted. Other Christian festivals have fixed dates.
CALENDAR, a system of measuring time by reference to recurring phenomena or to computed intervals.
Origins and development
The calendar is one of the oldest forms of applied science; its purpose is not merely to keep records, but also to predict developments. In a community whose livelihood depends on seasonal opportunities (e.g., for agriculture, or hunting, where the game moves with the seasons), one must know the right time for action.
Religion added incentives for prediction, in the general belief that sacrifices were required to insure success in agriculture or hunting; and success called for thanksgiving as well as joy. In true religion as in false, observances must be scheduled to enable the community to unite in fellowship, or consecration, or desire. It fell to the priests to maintain the calendar, a task certainly beyond the ability of the unskilled. The Samaritan claim was typical (Bowman, VetTest 15 , 120ff.); calculations depended partly on the correct text of instructions, partly on an expertise which only the priests could have.
As trade increased, a calendar became an essential basis for contracts. Within the more advanced communities, the functions of administration (esp. fiscal and judicial) needed a calendar to fix periods and systematize records. In government and trade, wider horizons and more sophisticated organization called for more compatible, standardized calendars.
An imperial power might impose its own calendar or adopt that of a conquered civilization. The Pers. conquerors of Babylon first adopted the Babylonian calendar, then imposed it throughout their later empire (Bickerman, p. 24). The Romans found no system in their Gr. dominions which commanded any wide acceptance; but their own calendar was so erratic that, eventually, Julius Caesar carried out a thorough reform. He did this without disturbing the festivals from their places within each month, or removing nominal control from the priests; as Segal says (JSS 6, 74ff.), a calendar which breaks completely with ancient traditions is not likely to survive for long. Caesar’s reconciliation of tradition and science gave Europe a stable solar calendar based on computation, and resolved the tension between conservative and systematizing tendencies.
While there is no absolute need to use a solar year, there are good practical reasons for matching everyday reckoning to the climatic cycle. The history of the calendar is largely concerned with the attempt to reconcile observational and climatic factors; the former proved more complex and subtle than was at first suspected.
Climatic changes (cyclic variations in the weather) control the growth and ripening of the earth’s produce: (1) rainfall promotes growth directly, and causes rivers to appear or rise, sometimes in countries which do not themselves receive appreciable rain; (2) insolation, varying with the sun’s altitude, affects the heat of the earth and hence of the atmosphere; this in turn affects the prevailing winds and the rainfall. All climatic conditions, the seasons, and the growth of crops, depend ultimately on the sun and on the fact that the earth’s axis is not perpendicular to the ecliptic.
In many parts of the world, the heating of the land during the day produces an onshore wind, if meteorological conditions are otherwise stable.
Daily change in the sun’s meridian altitude corresponds to the climatic cycle. It is possible, but it requires skill and apparatus, to determine the solstices and equinoxes to within a day. The solar or tropic year is approximately 365.24 mean solar days. Since the earth’s orbit is slightly elliptic, the fall equinox comes about 186 days after the spring (vernal) equinox.
The moon’s phases are readily observed, but less easy to determine precisely, except for the phasis; even here, since the moon moves half a degree eastward (relative to the sun) in each hour, the crescent might be seen in Pal. on a night when it had not appeared in Babylonia; cloud or haze may also hinder observation. The altitude of the crescent varies, partly because of the varying inclination of the ecliptic to the horizon, partly because the moon may be up to five degrees N or S of the sun. The moon’s synodic period (lunation) is about 29.53 days.
The stars are the most accurate indicators of time; being so far from the earth, they appeared fixed until astronomers could make precise measurements. From the point of view of the man-in-the-field, their unvarying pattern goes through an annual cycle corresponding to the sun’s movement against the stellar backcloth. A constellation appears farther to the W each evening, until it no longer appears before sunset. Soon afterwards, it becomes visible in the E before dawn (heliacal rising) and rises earlier each night until it is again visible at sunset.
From very early times the stellar cycle was associated with the seasons, but only after many centuries did the annual shift become apparent. Precision causes (a) a shift of the solstices and equinoxes with reference to the Zodiac; (b) a shift of the equatorial plane in relation to the ecliptic, so that stars which once rose or culminated at the same time no longer do so.
Shabua’ (seven-day period) occurs in the OT, mainly in connection with the
Yeraḥ (Akkad.) from yāreaḥ, the moon (as a visible object) is used (a) for a lunation; (b) for a specific month; (c) in counting months. Hōḏesh, from hāḏāsh, new, meaning the crescent or the day of its appearance, hence the reference for dating within a month; found throughout the OT as a common synonym for yeraḥ. See New Moon.
For yāmīm, days, see above (1.h). Shānāh, turning or change, the great cycle which governs all human activity. Connected with it are: T’qūp̱āh, circuit (
Celestial sphere: the imaginary background on which the movements of the heavenly bodies, as seen from the earth, can be traced. Position is defined by degrees of declination from the celestial equator toward the N or S celestial poles (corresponding to latitude), and by right ascension in hours eastward from the vernal equinox, which is the prime reference.
Conjunction: the position of two bodies being in the same direction (longitude) from the earth.
Ecliptic: the apparent path of the sun on the celestial sphere. The plane of the ecliptic is the fundamental reference for the solar system.
Epact (annual): the difference in time between the lunar and solar years (about eleven days).
Epagomenal Days: days added in the calendar to compensate the epact or other such difference; distinct from intercalary days as being part of the calendar and not an interruption of it.
Equinox: point on the celestial sphere where the ecliptic intersects the equator. At the vernal equinox the sun passes from N to S declination.
: the remainder from dividing a year date ( ) by 19, plus 1. This defines the moon’s phases (and all dependent dates) for that year, in accordance with the Metonic cycle.
Heliacal rising: the annual date when a star is seen to rise immediately before dawn. Though not a very precise observation, it was the best way of determining a point in the solar year before accurately calibrated instruments were available.
Intercalation: interruption of calendar sequence to insert an extra unit, ad hoc or regularly.
Longitude: measurement of degrees eastward from the vernal equinox in the ecliptic plane.
Lunation: period between two conjunctions of the moon and the sun (also synodic month).
Metonic Cycle: period of nineteen years, after which the moon’s phases repeat their celestial positions; discovered by the Gr. astronomer Meton in the 5th cent. b.c. The inaccuracy is only one day in twelve cycles (228 years).
Phase (lunar): the appearance of the moon at a given point in its orbit round the earth.
Phasis: the first appearance of the new moon.
Precession: a steady oscillation of the earth’s axis in relation to the ecliptic, in a period of 25,800 years. With reference to the fixed stars, the equinoxes move around the ecliptic, being now 70o from their position in 3000 b.c. The Taurus period denotes the time before about 2500 b.c., when the vernal equinox was in Taurus.
Solstice: time when the sun reaches its maximum declination; position of the sun at this time.
Year: a solar or tropic year is the time in which the sun returns to the vernal equinox. A lunar year is twelve lunations.
Zodiac: the ecliptic divided into twelve zones of 30o for computational purposes, named in Babylonian times after the constellations in the zones.
Names of months.
Hebrew calendars and their derivatives.
The agricultural year ended at the harvest of grapes and fruit (
Numbering of the months, from the passover month (
The Jews had a lunisolar calendar on the Babylonian model, intercalating a second Adar and eventually standardizing seven intercalations in nineteen years, though the Mishnaic rules leave the final decision in the hands of the Sanhedrin. According to the tractate Rosh hashshanah, great attention was paid to the observation of the new moon; but it was laid down that there could not be more than seven, nor fewer than five, thirty-day months in any year.
a. The refers to a calendar of much interest, which abandoned the lunar month for one of thirty days. The year was divided into quarters, each of three months and an epagomenal day (i.e., thirteen weeks), so that all dates fell always on the same day of the week, and festivals never clashed with the sabbath. At the same time, it kept clear of Hel. systems which, like the Babylonian, were tending to a nineteen-year cycle.
The discovery of Jubilees texts at Qumran has revived debate as to whether this calendar could ever have been used in a community. It would have meant abandoning the solar year; no scheme of intercalation seems to avoid compromising its fundamental principles.
b. Qumran. Discrepancy between the orthodox and “covenanter” calendars was a major ground of contention, illustrated by the story that the Wicked Priest affronted the Teacher of Righteousness on what the Teacher, but evidently not the Priest, held to be the . Qumran seems to have agreed with Jubilees at least in regarding the week as primary, and the calendar as a matter of revelation. Reference to the moon is disputed (Talmon, Scripta Hierosoly mitana 4 ; Bowman PEQ 1959). Kutsch (Vet Test 11) considers intercalation only of weeks, but Vogt (Biblica 39) believes that it was used to reconcile Essene and solar years.
c. Samaritan. The Tolidah shows points of contact with Jubilees; but certain prayers show that the month could begin on the sabbath. Baumgarten (Vet Test 16) regards the calendar as basically lunar.
d. Elephantine. The syncretistic community here, prob. from Northern Israel, used Pers. (i.e., Babylonian) and Egyp. dating, but observed at least the Passover according to Jewish tradition.
Theories of development.
does not describe a calendar; it assumes a lunisolar basis. The historical books only give information sporadically; little is known of the observance of festivals under the Judges, or during the ebb and flow of religion under the kings. A series of articles by J. Morgenstern in HUCA demonstrates the scope available to speculation. His theory of an original “Canaanite” solar calendar, replaced in the 6th cent. by one of Babylonian type, was later withdrawn (JBL 83, Vet Test 5) in favor of the pentecontad theory of J. and H. Lewy; both ignore the evidence of the Gezer Calendar and the OT references to the new moon. Derivation of a pentecontad (fifty-day period) from a module of seven, squared and “rounded up,” is suspect both in assumptions and logic (fifty is not “round” unless a base other than seven is already used). Segal (Vet Test 7) points out that natural events rather than computed intervals must dominate the calendar of an agricultural people.
In HUCA XXI, Morgenstern redefined Solomon’s calendar as lunisolar and “Tyrian” (376f.); after many vicissitudes, the pentecontad was revived by the deuteronomists (433), although they numbered the months ordinally (436). Many inconsistencies reveal the unsound methodology of these theories.
Calendars were developed by each of the principal cities; that of Nippur, adopted by Sargon I, became standard. The text enbu bel arḥim (Nineveh, 7th cent.) is the oldest full account, but some “menologies” of propitious and unlucky days date from the second millennium. The earliest calendars were prob. lunisolar; according to Langdon, intercalation was used to keep the barley harvest in Adar. A cycle of seven intercalations in nineteen years was in use by the 4th cent.; but a 7th cent. prism provides for beginning a year at the new moon nearest the vernal equinox. By the 2nd cent. conjunction and phasis were found by computation.
Little is known beyond the names of certain months (Ethanim, Bul as in
The Egyp. year began at the Nile flood, and was divided into four seasons of three months. The heliacal rising of Sirius marked this year; but the official calendar (twelve months of thirty days, and five epagomenal) was allowed to creep forward, rotating through the year in what became known as the “Sothic” (Sirius) cycle.
State calendars were the responsibility of the magistrates; varying use was made of the schemes proposed by astronomers for establishing a regular cycle of intercalation. The Macedonian calendar, known chiefly from its use in Egypt by the Ptolemies, had months of twenty-nine days and thirty, alternately; intercalation was irregular. By 117 b.c., the Egyp. calendar was readopted, using Macedonian month names. The Seleucids used the Babylonian calendar with Macedonian names.
Many features of our calendar are Rom. in origin; the January new year (adopted 53 b.c.), the short February, and the names of the months. The Romans neither observed a lunar month, nor did they master intercalation. Caesar introduced a solar year based on a value of 365 1/4 days, which Hipparchus had already shown to be slightly too large; but as the cumulative error is only a day in a cent., it continues to serve, with the Gregorian adjustment.
The new year.
Both spring and fall new years are recognized in the Pentateuch (e.g.,
Date of the Passover.
In the Pentateuch, the Passover is firmly dated on the fourteenth day of the first month; but the lack of any historical reference between Joshua (
The Day of Atonement (
Morgenstern (HUCA I, 22f.) argues from
The northern kingdom.
instituted a feast at Bethel on the fifteenth of the eighth month. This may well reflect the later harvest in the N; and if he, in fact, altered the calendar by one lunar month, this may partly explain the second month Passover of Hezekiah when he was canvassing support in Israel (Talmon, Vet Test 8).
Shabbāt (pause, rest) was prob. not derived from sheḇa’ (seven). A cognate Akkad. sapattu denoted the fifteenth of a month, though it may have been used earlier for the epagomenal period (Lewy, HUCA XVII, 78ff.); the 7th, 14th and 28th, though esp. marked, were not restdays in our sense; cf. Langdon p. 83. See Sabbath.
B. Landsberger, Der Kult. Kalendar (1915); P. Nilsson, Primitive Time Reckoning (1920); J. Morgenstern, HUCA I (1924), 13-78; G. Dalman, Arbeit u. Sitte I (1927); S. Langdon, Babylonian Menologies (1933); J. and H. Lewy, HUCA 17 (1941), 1-152; J. Morgenstern, HUCA 20 (1947), 1-36, 21 (1948), 365-496; R. Parker, Calendars of Ancient Egypt (1950); A. Jaubert, Vet Test 3 (1953), 250-264; S. Horn and L. Wood, JNES 13 (1954), 1-20; R. Parker, JNES 14 (1955), 271ff.; J. Morgenstern, Vet Test 5 (1955), 35-76; R. North, Biblica 36 (1955), 82-201; J. Obermann, JBL 75 (1956), 285-297; O. Neugebauer, Exact Sciences in Antiquity2 (1957); A. Jaubert, Vet Test 7 (1957), 35-61; J. Segal, ibid., 250-307; E. Vogt, Biblica 39 (1958), 72-77; S. Talmon, Vet Test 8 (1958), 48-74; E. Auerbach, ibid., 337-343, Vet Test 9 (1959), 113-121; J. Bowman, PEQ (1959), 23-37; E. Kutsch, Vet Test 11 (1961), 39-47; F. North, ibid., 446-448; J. Segal, JSS 6 (1961), 74-94; B. Rahtjen, PEQ (1961), 70-72; S. Talmon, JAOS 83 (1963), 177-187; J. Morgenstern, JBL 83 (1964), 109-18; W. Hartner, JNES 24 (1965), 1-16; J. Baumgarten, Vet Test 16 (1966), 277-286; H. Stroes, ibid., 460-475; E. Bickerman, Chronology of the Ancient World (1968).
International Standard Bible Encyclopedia (1915)
The Hebrew or Jewish calendar had three stages of development: the preexilic, or Biblical; the postexilic, or Talmudic; and the post-Talmudic. The first rested on observation merely, the second on observation coupled with calculation, and the third on calculation only. In the first period the priests determined the beginning of each month by the appearance of the new moon and the recurrence of the prescribed feasts from the vernal and autumnal equinoxes. Thus, the month Abib (’abhibh), the first month of the year according to the Levitical law, in which the Passover was to be celebrated, was determined by observation (
The year (shanah) originally began in the autumn, as appears from
The year was composed of 12 or 13 months according as to whether it was ordinary or leap year. Intercalation is not mentioned in Scripture, but it was employed to make the lunar correspond approximately to the solar year, a month being added whenever the discrepancy of the seasons rendered it necessary. This was regulated by the priests, who had to see that the feasts were duly observed at the proper season. The intercalary month was added after the month of ’Adhar and was called the second ’Adhar (sheni, wa-’adhar, "and Adar"), and, as already indicated, was added about once in 3 years. More exactly, 4 years out of every 11 were leap years of 13 months (Jewish Encyclopedia, article "Calendar"), this being derived from the Babylonian calendar. If, on the 16th of the month Nican, the sun had not reached the vernal equinox, that month was declared to be the second ’Adhar and the following one Nican. This method, of course, was not exact and about the 4th century of our era the mathematical method was adopted. The number of days in each month was fixed, seven having 30 days, and the rest 29. When the intercalary month was added, the first ’Adhar had 30 and the second 29 days.