Early Calendars

Before the invention of the clock, people watched the sun, the moon, and the stars to tell time.

The daily rising of the sun provided a short unit of time, the solar day.

The cycle of seasons roughly indicated a longer unit of time, the solar year.

Early civilizations did not know that the earth's revolution around the sun caused the different seasons.

Celestial Observatories such as Stonehenge

were used as celestial calendars to mark seasons.

Early calendars used to measure the intervals between the successive full moons, called the lunar month, as an intermediate unit of time.

We now know that the lunar month lasts about 29 1/2 days. Twelve such months amount to about 354 days. This interval is almost 11 days shorter than the true solar year, which has 365 days, 5 hours, 48 minutes, and 46 seconds. But a year of 13 lunar months would amount to about 383 1/2 days and would be more than 18 days longer than the solar year. The solar year, therefore, does not equal any whole number of lunar months.

The discrepancy between whole lunar months and days in a solar year explains the confusion over calendar keeping during thousands of years. A calendar based on 12 lunar months becomes out of step with the seasons. Some people who used lunar calendars kept them roughly in step with the seasons by making some years 12 months long and other years 13 months long.

Early calendars usually represented some sort of compromise between the lunar and solar years. Some years lasted 12 months, and others lasted 13 months.

Jewish Calendar

The calendar in Jewish history. Present knowledge of the Jewish calendar in use before the period of the Babylonian Exile is both limited and uncertain.

The Bible refers to calendar matters only incidentally, and the dating of components of Mosaic Law remains doubtful. The earliest datable source for the Hebrew calendar is the Gezer Calendar, written probably in the age of Solomon, in the late 10th century BC.

The inscription indicates the length of main agricultural tasks within the cycle of 12 lunations. The calendar term here is yereah, which in Hebrew denotes both "moon" and "month."

The second Hebrew term for month, hodesh, properly means the "newness" of the lunar crescent.

Thus, the Hebrew months were lunar. They are not named in pre-exilic sources except in the biblical report of the building of Solomon's Temple in I Kings, where the names of three months, two of them also attested in the Phoenician calendar, are given; the months are usually numbered rather than named.

The "beginning of the months" was the month of the Passover (see Judaism: The cycle of the religious year).

In some passages, the Passover month is that of hodesh ha-aviv, the lunation that coincides with the barley being in the ear.

Thus, the Hebrew calendar is tied in with the course of the Sun, which determines ripening of the grain.

It is not known how the lunar year of 354 days was adjusted to the solar year of 365 days.

The Bible never mentions intercalation. The year shana, properly "change" (of seasons), was the agricultural and, thus, liturgical year. There is no reference to the New Year's day in the Bible.

After the conquest of Jerusalem (587 BC), the Babylonians introduced their cyclic calendar (see above Babylonian calendars) and the reckoning of their regnal years from Nisanu 1, about the spring equinox. The Jews now had a finite calendar year with a New Year's day, and they adopted the Babylonian month names, which they continue to use. From 587 BC until AD 70, the Jewish civil year was Babylonian, except for the period of Alexander the Great and the Ptolemies (332-200 BC), when the Macedonian calendar was used.

The situation after the destruction of the Temple in Jerusalem in AD 70 remains unclear. It is not known whether the Romans introduced their Julian calendar or the calendar that the Jews of Palestine used after AD 70 for their business transactions. There is no calendar reference in the New Testament; the contemporary Aramaic documents from Judaea are rare and prove only that the Jews dated events according to the years of the Roman emperors. The abundant data in the Talmudic sources concern only the religious calendar.

In the religious calendar, the commencement of the month was determined by the observation of the crescent New Moon, and the date of the Passover was tied in with the ripening of barley. The actual witnessing of the New Moon and observing of the stand of crops in Judaea were required for the functioning of the religious calendar.

The Jews of the Diaspora, or Dispersion, who generally used the civil calendar of their respective countries, were informed by messengers from Palestine about the coming festivals. This practice is already attested for 143 BC. After the destruction of the Temple in AD 70, rabbinic leaders took over from the priests the fixing of the religious calendar. Visual observation of the New Moon was supplemented and toward AD 200, in fact, supplanted by secret astronomical calculation.

But the people of the Diaspora were often reluctant to wait for the arbitrary decision of the calendar makers in the Holy Land. Thus, in Syrian Antioch in AD 328-342, the Passover was always celebrated in (Julian) March, the month of the spring equinox, without regard to the Palestinian rules and rulings. To preserve the unity of Israel, the patriarch Hillel II, in 358/359, published the "secret" of calendar making, which essentially consisted of the use of the Babylonian 19-year cycle with some modifications required by the Jewish ritual.

The application of these principles occasioned controversies as late as the 10th century AD. In the 8th century, the Karaites, following Muslim practice, returned to the actual observation of the crescent New Moon and of the stand of barley in Judaea. But some centuries later they also had to use a precalculated calendar. The Samaritans, likewise, used a computed calendar.

Because of the importance of the Sabbath as a time divider, the seven-day week served as a time unit in Jewish worship and life. As long as the length of a year and of every month remained unpredictable, it was convenient to count weeks. The origin of the biblical septenary, or seven-day, week remains unknown; its days were counted from the Sabbath (Saturday for the Jews and Sunday for Christians).

A visionary, probably writing in the Persian or early Hellenistic age under the name of the prediluvian Enoch, suggested the religious calendar of 364 days, or 52 weeks, based on the week, in which all festivals always fall on the same weekday. His idea was later taken up by the Qumran community. (E.J.Bi.)

The structure of the calendar

The Jewish calendar in use today is lunisolar, the years being solar and the months lunar, but it also allows for a week of seven days. Because the year exceeds 12 lunar months by about 11 days, a 13th month of 30 days is intercalated in the third, sixth, eighth, 11th, 14th, 17th, and 19th years of a 19-year cycle. For practical purposes--e.g., for reckoning the commencement of the Sabbath--the day begins at sunset; but the calendar day of 24 hours always begins at 6 PM. The hour is divided into 1,080 parts (halaqim; this division is originally Babylonian), each part (heleq) equalling 3 1/3 seconds. The heleq is further divided into 76 rega'im.

The synodic month is the average interval between two mean conjunctions of the Sun and Moon, when these bodies are as near as possible in the sky, which is reckoned at 29 days 12 hours 44 minutes 3 1/3 seconds; a conjunction is called a molad. This is also a Babylonian value. In the calendar month, however, only complete days are reckoned, the "full" month containing 30 days and the "defective" month 29 days.

The months Nisan, Sivan (Siwan), Av, Tishri, Shevat, and, in a leap year, First Adar are always full; Iyyar, Tammuz, Elul, Tevet, and Adar (known as Second Adar, or Adar Sheni, in a leap year) are always defective, while Heshvan (Heshwan) and Kislev (Kislew) vary. The calendar, thus, is schematic and independent of the true New Moon.

The number of days in a year varies. The number of days in a synodic month multiplied by 12 in a common year and by 13 in a leap year would yield fractional figures. Hence, again reckoning complete days only, the common year has 353, 354, or 355 days and the leap year 383, 384, or 385 days.

A year in which both Heshvan and Kislev are full, called complete (shelema), has 355 or (if a leap year) 385 days; a normal (sedura) year, in which Heshvan is defective and Kislev full, has 354 or 384 days; while a defective (hasera) year, in which both these months are defective, has 353 or 383 days.

The character of a year (qevi'a, literally "fixing") is described by three letters of the Hebrew alphabet, the first and third giving, respectively, the days of the weeks on which the New Year occurs and Passover begins, while the second is the initial of the Hebrew word for defective, normal, or complete.

There are 14 types of qevi'ot,seven in common and seven in leap years. The New Year begins on Tishri 1, which may be the day of the molad of Tishri but is often delayed by one or two days for various reasons.

Thus, in order to prevent the Day of Atonement (Tishri 10) from falling on a Friday or a Sunday and the seventh day of Tabernacles (Tishri 21) from falling on a Saturday, the New Year must avoid commencing on Sundays, Wednesdays, or Fridays.

Again, if the molad of Tishri occurs at noon or later, the New Year is delayed by one or, if this would cause it to fall as above, two days. These delays (dehiyyot) necessitate, by reason of the above-mentioned limits on the number of days in the year, two other delays.

The mean beginning of the four seasons is called tequfa (literally "orbit," or "course"); the tequfa of Nisan denotes the mean Sun at the vernal equinox, that of Tammuz at the summer solstice, that of Tishri at the autumnal equinox, and that of Tevet at the winter solstice.

As 52 weeks are the equivalent to 364 days, and the length of the solar year is nearly 365 1/4 days, the tequfot move forward in the week by about 1 1/4 days each year.

Accordingly, reckoning the length of the year at the approximate value of 365 1/4 days, they are held to revert after 28 years (28 1 1/4 = 35 days) to the same hour on the same day of the week (Tuesday, 6 PM) as at the beginning.

This cycle is called the great, or solar, cycle (mahzor gadol or hamma). The present Jewish calendar is mainly based on the more accurate value 365 days, 5 hours, 55 minutes, 25 25/57 seconds--in excess of the true tropical year by about 6 minutes 40 seconds.

Thus, it is advanced by one day in about 228 years with regard to the equinox.

To a far greater extent than the solar cycle of 28 years, the Jewish calendar employs, as mentioned above, a small, or lunar, cycle (mahzor qatan) of 19 years, adjusting the lunar months to the solar years by intercalations. Passover, on Nisan 14, is not to begin before the spring tequfa, and so the intercalary month is added after Adar. The mahzor qatan is akin to the Metonic cycle described above.

The Jewish Era in use today is that dated from the supposed year of the Creation (designated anno mundi or AM) with its epoch, or beginning, in 3761 BC. For example, the Jewish year 5745 AM, the 7th in the 303rd lunar cycle and the 5th in the 206th solar cycle, is a regular year of 12 months, or 354 days.

The qevi'ais, using the three respective letters of the Hebrew alphabet as two numerals and an initial in the manner indicated above, HKZ, which indicates that Rosh Hashana (New Year) begins on the fifth (H = 5) and Passover on the seventh (Z = 7) day of the week and that the year is regular (K = ke-sidra); i.e., Heshvan is defective--29 days, and Kislev full--30 days. The Jewish year 5745 AM corresponds with the Christian Era period that began September 27, 1984, and ended September 15, 1985.

Neglecting the thousands, current Jewish years AM are converted into years of the current Christian Era by adding 239 or 240--239 from the Jewish New Year (about September) to December 31 and 240 from January 1 to the eve of the Jewish New Year.

The adjustment differs slightly for the conversion of dates of now-antiquated versions of the Jewish Era of the Creation and the Christian Era, or both. Tables for the exact conversion of such dates are available.

Months and important days

The months of the Jewish year and the notable days are as follows: Tishri: 1-2, Rosh Hashana (New Year); 3, Fast of Gedaliah; 10, Yom Kippur (Day of Atonement); 15-21, Sukkot (Tabernacles); 22, Shemini Atzeret (Eighth Day of Solemn Assembly); 23, Simhat Torah (Rejoicing of the Law).

Heshvan. Kislev: 25, Hanukka (Festival of Lights) begins. Tevet: 2 or 3, Hanukka ends; 10, Fast. Shevat: 15, New Year for Trees (Mishna). Adar: 13, Fast of Esther; 14-15, Purim (Lots). Second Adar (Adar Sheni) or ve-Adar (intercalated month);Adar holidays fall in ve-Adar during leap years. Nisan: 15-22, Pesah (Passover). Iyyar: 5, Israel Independence Day. Sivan: 6-7, Shavuot (Feast of Weeks [Pentecost]). Tammuz: 17, Fast (Mishna). Av: 9, Fast (Mishna). Elul. (E.J.Wi.)

Muslim Calendar

The Muslim Era is computed from the starting point of the year of the emigration (Hegira); that is, from the year in which Muhammad, the prophet of Islam, emigrated from Mecca to Medina, AD 622. The second caliph, 'Umar I, who reigned 634-644, set the first day of the month Muharram as the beginning of the year; that is, July 16, 622, which had already been fixed by the Qur'an as the first day of the year.

The years of the Muslim calendar are lunar and always consist of 12 lunar months alternately 30 and 29 days long, beginning with the approximate New Moon. The year has 354 days, but the last month (Dhu al-Hijjah) sometimes has an intercalated day, bringing it up to 30 days and making a total of 355 days for that year. The months do not keep to the same seasons in relation to the Sun, because there are no intercalations of months. The months regress through all the seasons every 32 1/2 years.

Ramadan, the ninth month, is observed throughout the Muslim world as a month of fasting. According to the Qur'an, Muslims must see the New Moon with the naked eye before they can begin their fast. The practice has arisen that two witnesses should testify to this before a qadi (judge), who, if satisfied, communicates the news to the mufti (the interpreter of Muslim law), who orders the beginning of the fast. It has become usual for Middle Eastern Arab countries to accept, with reservations, the verdict of Cairo. Should the New Moon prove to be invisible, then the month Sha'ban, immediately preceding Ramadan, will be reckoned as 30 days in length, and the fast will begin on the day following the last day of this month. The end of the fast follows the same procedure.

The era of the Hegira is the official era in Saudi Arabia, Yemen, and the principalities of the Persian Gulf. Egypt, Syria, Jordan, and Morocco use both the Muslim and the Christian eras. In all Muslim countries, people use the Muslim Era in private, even though the Christian Era may be in official use.

Some Muslim countries have made a compromise on this matter. Turkey, as early as 1088 AH (AD 1677), took over the solar (Julian) year with its month names but kept the Muslim Era. March 1 was taken as the beginning of the year (commonly called marti year, after the Turkish word mart, for March). Late in the 19th century, the Gregorian calendar was adopted.

In the 20th century, Pres. Mustafa Kemal Atat�rk ordered a complete change to the Christian Era. Iran, under Reza Shah Pahlavi (reigned 1925-41), also adopted the solar year but with Persian names for the months and keeping the Muslim Era. March 21 is the beginning of the Iranian year. Thus, the Iranian year 1359 began on March 21, 1980. This era is still in use officially. (See also Islam: Sacred places and days.)

Hindu Calendar

While the Republic of India has adopted the Gregorian calendar for its secular life, its Hindu religious life continues to be governed by the traditional Hindu calendar. This calendar, based primarily on the lunar revolutions, is adapted to solar reckoning.

Early history

The oldest system, in many respects the basis of the classical one, is known from texts of about 1000 BC. It divides an approximate solar year of 360 days into 12 lunar months of 27 (according to the early Vedic text Taittiriya Samhita or 28 (according to the Atharvaveda, the fourth of the Vedas, 19.7.1.) days. The resulting discrepancy was resolved by the intercalation of a leap month every 60 months.

Time was reckoned by the position marked off in constellations on the ecliptic in which the Moon rises daily in the course of one lunation (the period from New Moon to New Moon) and the Sun rises monthly in the course of one year.

These constellations (naksatra) each measure an arc of 13 20' of the ecliptic circle.

The positions of the Moon were directly observable, and those of the Sun inferred from the Moon's position at Full Moon, when the Sun is on the opposite side of the Moon. The position of the Sun at midnight was calculated from the naksatra that culminated on the meridian at that time, the Sun then being in opposition to that naksatra.

The year was divided into three thirds of four months, each of which would be introduced by a special religious rite, the caturmasya (four-month rite). Each of these periods was further divided into two parts (seasons or rtu): spring (vasanta), from mid-March until mid-May; summer (grisma), from mid-May until mid-July; the rains (varsa), from mid-July until mid-September; autumn (sarad ), from mid-September until mid-November; winter (hemanta), from mid-November until mid-January; and the dews (sisira), from mid-January until mid-March.

The spring months in early times were Madhu and Madhava, the summer months Sukra and Suci, the rainy months Nabhas and Nabhasya, the autumn months Isa and Urja, the winter months Sahas and Sahasya, and the dewy months Tapas and Tapasya.

The month, counted from Full Moon to Full Moon, was divided into two halves (paksa, "wing") of waning (krsna) and waxing (sukla) Moon, and a special ritual (darsapurnamasa, "new and full moon rites") was prescribed on the days of New Moon (amavasya) and Full Moon (purnimas).

The month had theoretically 30 days (tithi; see below), and the day (divasa) 30 hours (muhurta).

This picture is essentially confirmed by the first treatise on time reckoning, the Jyotisa-vedanga ("Vedic auxiliary [text] concerning the luminaries") of about 100 BC, which adds a larger unit of five years (yuga) to the divisions. A further old distinction is that of two year moieties, the uttarayana ("northern course"), when the Sun has passed the spring equinox and rises every morning farther north, and the daksinayana ("southern course"), when it has passed the autumnal equinox and rises progressively farther south.

The classical calendar

In its classic form (Surya-siddhanta, 4th century AD) the calendar continues from the one above with some refinements. With the influence of Hellenism, Greek and Mesopotamian astronomy and astrology were introduced.

Though astronomy and time reckoning previously were dictated by the requirements of rituals, the time of which had to be fixed correctly, and not for purposes of divination, the new astrology came into vogue for casting horoscopes and making predictions.

Zodiacal time measurement was now used side by side with the older naksatra one. The naksatra section of the ecliptic (13 20') was divided into four parts of 3 20' each; thus, two full naksatras and a quarter of one make up one zodiac period, or sign (30).

The year began with the entry of the Sun (samkranti) in the sign of Aries. The names of the signs (rasi) were taken over and mostly translated into Sanskrit: mesa ("ram," Aries), vrsabha ("bull," Taurus), mithuna ("pair," Gemini), karkata ("crab," Cancer), simha ("lion," Leo), kanya ("maiden," Virgo), tula ("scale," Libra), vrscika ("scorpion," Scorpius), dhanus ("bow," Sagittarius), makara ("crocodile," Capricornus), kumbha ("water jar," Aquarius), mina ("fish," Pisces).

The precession of the vernal equinox from the Sun's entry into Aries to some point in Pisces, with similar consequences for the summer solstice, autumnal equinox, and winter solstice, has led to two different methods of calculating the samkranti (entry) of the Sun into a sign. The precession (ayana) is not accounted for in the nirayana system (without ayana), which thus dates the actual samkranti correctly but identifies it wrongly with the equinox or solstice, and the sayana system (with ayana), which thus dates the equinox and solstice correctly but identifies it wrongly with the samkranti.

While the solar system has extreme importance for astrology, which, it is claimed, governs a person's life as an individual or part of a social system, the sacred time continues to be reckoned by the lunar naksatra system. The lunar day (tithi), a 30th part of the lunar month, remains the basic unit. Thus, as the lunar month is only about 29 1/2 solar days, the tithi does not coincide with the natural day (ahoratra). The convention is that that tithi is in force for the natural day that happened to occur at the dawn of that day. Therefore, a tithi beginning after dawn one day and expiring before dawn the next day is eliminated, not being counted in that month, and there is a break in the day sequence.

The names of the naksatras, to which correspond the tithis in the monthly lunar cycle and segments of months in the annual solar cycle, are derived from the constellations on the horizon at that time and have remained the same. The names of the months have changed: Caitra (March-April), Vaisakha (April-May), Jyaistha (May-June), Asadha (June-July), Sravana (July-August), Bhadrapada (August-September), Asvina (September-October), Karttika (October-November), Margasirsa (November-December), Pausa (December-January), Magha (January-February), and Phalguna (February-March).

In this calendar the date of an event takes the following form: month, fortnight (either waning or waxing Moon), name (usually the number) of the tithi in that fortnight, and the year of that era which the writer follows. Identification, particularly of the tithi, is often quite complicated, since it requires knowledge of the time of sunrise on that day and which 30th of the lunar month was in force then. Eventually, India also adopted the seven-day week (saptaha) from the West and named the days after the corresponding planets: Sunday after the Sun, ravivara; Monday after the Moon, somavara; Tuesday after Mars, mangalavara; Wednesday after Mercury, budhavara; Thursday after Jupiter, brhaspativara; Friday after Venus, sukravara; and Saturday after Saturn, sanivara.

A further refinement of the calendar was the introduction into dating of the place of a year according to its position in relation to the orbital revolution of the planet Jupiter, called brhaspati in Sanskrit. Jupiter has a sidereal period (its movement with respect to the "fixed" stars) of 11 years, 314 days, and 839 minutes, so in nearly 12 years it is back into conjunction with those stars from which it began its orbit. Its synodic period brings it into conjunction with the Sun every 398 days and 88 minutes, a little more than a year.

Thus, Jupiter in a period of almost 12 years passes about the same series of naksatras that the Sun passes in one year and, in a year, about the same naksatras as the Sun in a month. A year then can be dated as the month of a 12-year cycle of Jupiter, and the date is given as, for example, grand month of Caitra. This is extended to a unit of five cycles, or the 60-year cycle of Jupiter (brhaspaticakra), and a "century" of 60 years is formed. This system is known from the 6th century AD onward.

At the other end of the scale, more precision is brought to the day. Every tithi is divided into two halves, called karanas. The natural day is divided into units ranging from a vipala (0.4 second) to a ghatik) (24 minutes) and an "hour" (muhurta) of 48 minutes; the full natural day has 30 such hours. The day starts at dawn; the first six ghatikas are early morning, the second set of six midmorning, the third midday, the fourth afternoon, the fifth evening. Night lasts through three units (yama) of time: six ghatikas after sundown, or early night; two of midnight; and four of dawn.

The sacred calendar

There are a few secular state holidays (e.g., Independence Day) and some solar holidays, such as the entry of the Sun into the sign of Aries (mesa-samkranti), marking the beginning of the new astrological year; the Sun's entry into the sign of Capricornus (makara-samkranti), which marks the winter solstice but has coalesced with a hoary harvest festival, which in southern India is very widely celebrated as the Pongal festival; and the mahavisuva day, which is New Year's Eve. But all other important festivals are based on the lunar calendar.

As a result of the high specialization of deities and events celebrated in different regions, there are hundreds of such festivals, most of which are observed in smaller areas, though some have followings throughout India. A highly selective list of the major ones, national and regional, follows. (See also Hinduism: Sacred times and places.) Ramanavami ("ninth of Rama"), on Caitra S. (= sukla, "waxing fortnight") 9, celebrates the birth of Rama.

Rathayatra ("pilgrimage of the chariot"), Asadha S. 2, is the famous Juggernaut (Jagannatha) festival of the temple complex at Puri, Orissa. Janmastami ("eighth day of the birth"), Sravana K. (= krsna, "waning fortnight") 8, is the birthday of the god Krsna. Ganesacaturthi ("fourth of Ganesa"), Bhadrapada S. 4, is observed in honour of the elephant-headed god Ganhsa, a particular favourite of Maharashtra. Durga-puja ("homage to DurgaT), Asvina S. 7-10, is special to Bengal, in honour of the destructive and creative goddess Durga. Dasahra ("ten days"), or Dussera, Asvina 7-10, is parallel to Durga-puja, celebrating Rama's victory over Ravana, and traditionally the beginning of the warring season.

Laksmipuja ("homage to Laksmi"), Asvina S. 15, is the date on which commercial books are closed, new annual records begun, and business paraphernalia honoured; for Laksmi is the goddess of good fortune.

Dipavali, Diwali ("strings of lights"), Karttika K. 15 and S. 1, is the festival of lights, when light is carried from the waning to the waxing fortnight and presents are exchanged. Maha-sivaratri ("great night of Siva"), Magha K. 13, is when the dangerous but, if placated, benevolent god Siva is honoured on the blackest night of the month. Holi (name of a demoness), Phalguna S. 14, is a fertility and role-changing festival, scene of great fun-poking at superiors. Dolayatra ("swing festival"), Phalguna S. 15, is the scene of the famous hook-swinging rites of Orissa. Guru Nanak Jayanti, Karttika S. 15, is the birthday of Nanak, the founder of the sect of Sikhism.

The eras

Not before the first century BC is there any evidence that the years of events were recorded in well-defined eras, whether by cycles, as the Olympic Games in Greece and the tenures of consuls in Rome, or the Roman year dating from the foundation of the city. Perhaps under outside influence, the recording of eras was begun at various times, but these were without universal appeal, and few have remained influential.

Among those are (1) the Vikrama era, begun 58 BC; (2) the Saka era, begun AD 78 (these two are the most commonly used); (3) the Gupta era, begun AD 320; (4) the Harsa era, begun AD 606. All these were dated from some significant historical event. Of more mythological interest is the Kali era (Kali being the latest and most decadent period in the system of the four Yugas), which is thought to have started either at dawn on February 18, 3102 BC, or at midnight between February 17 and 18 in that year.