The Ethiopian calendar or Eritrean calendar is the principal calendar used in Ethiopia and serves as the liturgical year for Christians in Eritrea and Ethiopia belonging to the Eritrean Orthodox Tewahedo Church, Ethiopian Orthodox Tewahedo Church, Eastern Catholic Churches, the Coptic Orthodox Church of Alexandria, Ethiopian-Eritrean Evangelicalism. It is a solar calendar which in turn derives from the Egyptian calendar, but like the Julian calendar, it adds a leap day every four years without exception, begins the year on August 29 or August 30 in the Julian calendar. A gap of 7–8 years between the Ethiopian and Gregorian calendars results from an alternative calculation in determining the date of the Annunciation. Like the Coptic calendar, the Ethiopic calendar has 12 months of 30 days plus 5 or 6 epagomenal days, which comprise a thirteenth month; the Ethiopian months begin on the same days as those of the Coptic calendar, but their names are in Ge'ez. A 6th epagomenal day is added every 4 years, without exception, on August 29 of the Julian calendar, 6 months before the corresponding Julian leap day.
Thus the first day of the Ethiopian year, 1 Mäskäräm, for years between 1900 and 2099, is September 11. However, it falls on September 12 in years before the Gregorian leap year. Enkutatash is the word for the Ethiopian New Year in Amharic, the official language of Ethiopia, while it is called Ri'se Awde Amet in Ge'ez, the term preferred by the Ethiopian & Eritrean Orthodox Tewahedo Churchs, it occurs on September 11th in the Gregorian Calendar. The Ethiopian Calendar Year 1998 Amätä Məhrät began on the Gregorian Calendar Year on September 11th, 2005. However, the Ethiopian Years 1992 and 1996 began on the Gregorian Dates of'September 12th 1999' and'2003' respectively; this date correspondence applies for the Gregorian years 1900 to 2099. The Ethiopian leap year is every four without exception, while Gregorian centurial years are only leap years when divisible by 400; as the Gregorian year 2000 is a leap year, the current correspondence lasts two centuries instead. The start of the Ethiopian year falls on August 30th.
This date corresponds to the Old-Style Julian Calendar. This deviation between the Julian and the Gregorian Calendar will increase with the passing of the time. You can observe the real start date in the future centuries in a Gregorian to Ethiopian Date Converter. To indicate the year and followers of the Eritrean churches today use the Incarnation Era, which dates from the Annunciation or Incarnation of Jesus on March 25, AD 9, as calculated by Annianus of Alexandria c. 400. Meanwhile, Europeans adopted the calculations made by Dionysius Exiguus in AD 525 instead, which placed the Annunciation 8 years earlier than had Annianus; this causes the Ethiopian year number to be 8 years less than the Gregorian year number from January 1 until September 10 or 11 7 years less for the remainder of the Gregorian year. In the past, a number of other eras for numbering years were widely used in Ethiopia and the Kingdom of Aksum; the most important era – once used by the Eastern Christianity, still used by the Coptic Orthodox Church of Alexandria – was the Era of Martyrs known as the Diocletian Era, or the era of Diocletian and the Martyrs, whose first year began on August 29, 284.
Respective to the Gregorian and Julian New Year's Days, 31⁄2 to 4 months the difference between the Era of Martyrs and the Anni Domini is 285 years. This is because in AD 525, Dionysius Exiguus decided to add 15 Metonic cycles to the existing 13 Metonic cycles of the Diocletian Era to obtain an entire 532 year medieval Easter cycle, whose first cycle ended with the year Era of Martyrs 247 equal to year DXXXI, it is because 532 is the product of the Metonic cycle of 19 years and the solar cycle of 28 years. Around AD 400, an Alexandrine monk called Panodoros fixed the Alexandrian Era, the date of creation, on 29 August 5493 BC. After the 6th century AD, the era was used by Ethiopian chronologists; the twelfth 532 year-cycle of this era began on 29 August AD 360, so 4×19 years after the Era of Martyrs. Bishop Anianos preferred the Annunciation style as 25 March, thus he shifted the Panodoros era by about six months, to begin on 25 March 5492 BC. In the Ethiopian calendar this was equivalent to 15 Magabit 5501 B.
C.. The Anno Mundi era remained in usage until the late 19th century; the 4 year leap-year cycle is associated with the four Evangelists: the first year after an Ethiopian leap year is named the John-year, followed by the Matthew-year, the Mark-year. The year with the 6th epagomenal day is traditionally designated as the Luke-year. There are no exceptions to the 4 year leap-year cycle, like the Julian calendar but unlike the Gregorian calendar; these dates are valid only from March 1900 to February 2100. This is because 1900 and 2100 are not leap years in the Gregorian calendar, while they are still leap year
The 15th century was the century which spans the Julian years 1401 to 1500. In Europe, the 15th century is seen as the bridge between the Late Middle Ages, the Early Renaissance, the Early modern period. Many technological and cultural developments of the 15th century can in retrospect be seen as heralding the "European miracle" of the following centuries. In religious history, the Roman Papacy was split in two parts in Europe for decades, until the Council of Constance; the division of the Catholic Church and the unrest associated with the Hussite movement would become factors in the rise of the Protestant Reformation in the following century. Constantinople, in what is today Turkey the capital of the Christian Byzantine Empire, falls to the emerging Muslim Ottoman Turks, marking the end of the tremendously influential Byzantine Empire and, for some historians, the end of the Middle Ages; the event forced Western Europeans to find a new trade route, adding further momentum to what was the beginning of the Age of Discovery, which would lead to the global mapping of the world.
Explorations by the Portuguese and Spanish led to European sightings of the Americas and the sea passage along Cape of Good Hope to India, in the last decade of the century. These expeditions ushered in the era of the Portuguese and Spanish colonial empires; the fall of Constantinople led to the migration of Greek scholars and texts to Italy, while Johannes Gutenberg's invention of the mechanical movable type began the Printing Press. These two events played key roles in the development of the Renaissance; the Spanish Reconquista leads to the final fall of the Emirate of Granada by the end of the century, ending over seven centuries of Muslim rule and returning Spain back to Christian rulers. The Hundred Years' War end with a decisive French victory over the English in the Battle of Castillon. Financial troubles in England following the conflict results in the Wars of the Roses, a series of dynastic wars for the throne of England; the conflicts end with the defeat of Richard III by Henry VII at the Battle of Bosworth Field, establishing the Tudor dynasty in the part of the century.
In Asia, under the rule of the Yongle Emperor, who built the Forbidden City and commanded Zheng He to explore the world overseas, the Ming Dynasty's territory reached its pinnacle. Tamerlane established a major empire in the Middle East and Central Asia, in order to revive the Mongol Empire. In Africa, the spread of Islam leads to the destruction of the Christian kingdoms of Nubia, by the end of the century leaving only Alodia; the vast Mali Empire teeters on the brink of collapse, under pressure from the rising Songhai Empire. In the Americas, both the Inca Empire and the Aztec Empire reach the peak of their influence. 1400s 1401: Dilawar Khan establishes the Malwa Sultanate in present-day central India 1402: Ottoman and Timurid Empires fight at the Battle of Ankara resulting in Timur's capture of Bayezid I. 1402: Sultanate of Malacca founded by Parameshwara. 1403: The Yongle Emperor moves the capital of China from Nanjing to Beijing. 1403: The settlement of the Canary Islands signals the beginning of the Spanish Empire.
1405–1433: Zheng He of China sails through the Indian Ocean to India and East Africa to spread China's influence and sovereignty. 1405: Paregreg war, Majapahit civil war of succession between Wikramawardhana against Wirabhumi. 1405–1407: The first voyage of Zheng He, a massive Ming dynasty naval expedition visited Java, Malacca, Aru and Lambri. 1410s 1410: The Battle of Grunwald is the decisive battle of the Polish–Lithuanian–Teutonic War leading to the downfall of the Teutonic Knights. 1410–1413: Foundation of St Andrews University in Scotland. 1414: Khizr Khan, deputised by Timur to be the governor of Multan, takes over Delhi founding the Sayyid dynasty. 1415: Henry the Navigator leads the conquest of Ceuta from the Moors marking the beginning of the Portuguese Empire. 1415: Battle of Agincourt fought between the Kingdom of England and France. 1415: Jan Hus is burned at the stake as a heretic at the Council of Constance.1420s 1420: Construction of the Chinese Forbidden City is completed in Beijing.
1420–1434: Hussite Wars in Bohemia. 1424: James I returns to Scotland after being held hostage under three Kings of England since 1406. 1424: Deva Raya II succeeds his father Veera Vijaya Bukka Raya as monarch of the Vijayanagara Empire. 1425: Catholic University of Leuven founded by Pope Martin V. 1429: Joan of Arc ends the Siege of Orléans and turns the tide of the Hundred Years' War. 1429: Queen Suhita succeeds Wikramawardhana as ruler of Majapahit.1430s 1431 January 9 – Pretrial investigations for Joan of Arc begin in Rouen, France under English occupation. March 3 – Pope Eugene IV succeeds Pope Martin V, to become the 207th pope. March 26 – The trial of Joan of Arc begins. May 30 – Nineteen-year-old Joan of Arc is burned at the stake. June 16 – the Teutonic Knights and Švitrigaila sign the Treaty of Christmemel, creating anti-Polish alliance September – Battle of Inverlochy: Donald Balloch defeats the Royalists. October 30 – Treaty of Medina del Campo, consolidating peace between Portugal and Castille.
December 16 – Henry VI of England is crowned King of France. 1438: Pachacuti founds the Inca Empire.1440s 1440: Eton College founded by Henry VI. 1440s: The Golden Horde breaks up into the Siberia Khanate, the Khanate of Kazan, the Astrakhan Khanate, the Crimean Khanate, the Great Horde. 1440–1469: Under Moctezuma I, the Aztecs become the dominant power in Mesoamerica. 1440: Oba Ewuare comes to power in the West African city of Benin, turns it into an empire. 1441: Jan van Eyck, Flemish painter, dies. 1441: Portuguese navigators cruise West
Ab urbe condita
Ab urbe condita, or Anno urbis conditæ abbreviated as AUC in either case, is a convention, used in antiquity and by classical historians to refer to a given year in Ancient Rome. Ab urbe condita means "from the founding of the City," while anno urbis conditæ means "in the year since the City's founding." Therefore, the traditional year of the foundation of Rome, 753 BC, would be written AUC 1, while AD 1 would be AUC 754. The foundation of the Empire in 27 BC would be AUC 727. Usage of the term was more common during the Renaissance, when editors sometimes added AUC to Roman manuscripts they published, giving the false impression that the convention was used in antiquity. In reality, the dominant method of identifying years in Roman times was to name the two consuls who held office that year. In late antiquity, regnal years were in use, as was the Diocletian era in Roman Egypt after AD 293, in the Byzantine Empire after AD 537, following a decree by Justinian; the traditional date for the founding of Rome, 21 April 753 BC, is due to Marcus Terentius Varro.
Varro may have used the consular list and called the year of the first consuls "ab urbe condita 245," accepting the 244-year interval from Dionysius of Halicarnassus for the kings after the foundation of Rome. The correctness of this calculation has not been confirmed. From the time of Claudius onward, this calculation superseded other contemporary calculations. Celebrating the anniversary of the city became part of imperial propaganda. Claudius was the first to hold magnificent celebrations in honor of the anniversary of the city, in AD 48, the eight hundredth year from the founding of the city. Hadrian and Antoninus Pius held similar celebrations, in AD 121, in AD 147 and AD 148, respectively. In AD 248, Philip the Arab celebrated Rome's first millennium, together with Ludi saeculares for Rome's alleged tenth sæculum. Coins from his reign commemorate the celebrations. A coin by a contender for the imperial throne, explicitly states "ear one thousand and first", an indication that the citizens of the empire had a sense of the beginning of a new era, a Sæculum Novum.
The Anno Domini year numbering was developed by a monk named Dionysius Exiguus in Rome in AD 525, as a result of his work on calculating the date of Easter. Dionysius did not use the AUC convention, but instead based his calculations on the Diocletian era; this convention had been in use since AD 293, the year of the tetrarchy, as it became impractical to use regnal years of the current emperor. In his Easter table, the year AD 532 was equated with the 248th regnal year of Diocletian; the table counted the years starting from the presumed birth of Christ, rather than the accession of the emperor Diocletian on 20 November AD 284, or as stated by Dionysius: "sed magis elegimus ab incarnatione Domini nostri Jesu Christi annorum tempora praenotare". Blackburn and Holford-Strevens review interpretations of Dionysius which place the Incarnation in 2 BC, 1 BC, or AD 1, it has been calculated that the year AD 1 corresponds to AUC 754, based on the epoch of Varro. Thus, AUC 1 = 753 BC AUC 753 = 1 BC AUC 754 = AD 1 AUC 1000 = AD 247 AUC 1229 = AD 476 AUC 2206 = AD 1453 AUC 2753 = AD 2000 AUC 2772 = AD 2019 List of Latin phrases
Balinese saka calendar
The Balinese saka calendar is one of two calendars used on the Indonesian island of Bali. Unlike the 210-day pawukon calendar, it is based on the phases of the Moon, is the same length as the Gregorian year. Based on a lunar calendar, the saka year comprises sasih, of 30 days each. However, because the lunar cycle is shorter than 30 days, the lunar year has a length of 354 or 355 days, the calendar is adjusted to prevent it losing synchronization with the lunar or solar cycles; the months are adjusted by allocating two lunar days to one solar day every 9 weeks. This day is called ngunalatri, Sanskrit for "minus one night". To stop the Saka from lagging behind the Gregorian calendar – as happens with the Islamic calendar, an extra month, known as an intercalary month, is added after the 11th month, or after the 12th month; the length of these months is calculated according to the normal 63-day cycle. An intercalary month is added whenever necessary to prevent the final day of the 7th month, known as Tilem Kapitu, from falling in the Gregorian month of December.
The names the twelve months are taken from a mixture of Old Balinese and Sanskrit words for 1 to 12, are as follows: Kasa Karo Katiga Kapat Kalima Kanem Kapitu Kawalu Kasanga Kadasa Jyestha SadhaEach month begins the day after a new moon and has 15 days of waxing moon until the full moon 15 days of waning, ending on the new moon. Both sets of days are numbered 1 to 15; the first day of the year is the day after the first new moon in March. Note, that Nyepi falls on the first day of Kadasa, that the years of the Saka era are counted from that date; the calendar is 78 years behind the Gregorian calendar, is calculated from the beginning of the Saka Era in India. It is used alongside the 210-day Balinese pawukon calendar, Balinese festivals can be calculated according to either year; the Indian saka calendar was used for royal decrees as early as the ninth century CE. The same calendar was used in Java until Sultan Agung replaced it with the Javanese calendar in 1633; the Balinese Hindu festival of Nyepi, the day of silence, marks the start of the Saka year.
Tilem Kepitu, the last day of the 7th month, is known as Siva Ratri, is a night dedicated to the god Shiva. Devotees stay up all meditate. There are another 24 ceremonial days in the Saka year celebrated at Purnama. Eiseman, Fred B. Jr, Bali: Sekalia and Niskala Volume I: Essays on Religion and Art pp 182–185, Periplus Editions, 1989 ISBN 0-945971-03-6 Haer, Debbie Guthrie. ISBN 981 3018 496 Hobart, Angela. ISBN 0 631 17687 X Ricklefs, M. C.
The traditional China calendar, or Former Calendar, Traditional Calendar or Lunar Calendar, is a lunisolar calendar which reckons years and days according to astronomical phenomena. It is defined by GB/T 33661-2017, "Calculation and promulgation of the Chinese calendar", issued by the Standardisation Administration of China on 12 May 2017. Although modern day China uses the Gregorian calendar, the traditional Chinese calendar governs holidays in China and in overseas Chinese communities, it lists the dates of traditional Chinese holidays and guides people in selecting auspicious days for weddings, moving, or starting a business. Like Chinese characters, variants of this calendar are used in different parts of the Chinese cultural sphere. Korea and the Ryukyu Islands adopted the calendar, it evolved into Korean and Ryukyuan calendars; the main difference from the traditional Chinese calendar is the use of different meridians, which leads to some astronomical events—and calendar events based on them—falling on different dates.
The traditional Japanese calendar derived from the Chinese calendar, but its official use in Japan was abolished in 1873 as part of reforms after the Meiji Restoration. Calendars in Mongolia and Tibet have absorbed elements of the traditional Chinese calendar, but are not direct descendants of it. Days begin and end at midnight, months begin on the day of the new moon. Years begin on the second new moon after the winter solstice. Solar terms govern the end of each month. Written versions in ancient China included stems and branches of the year and the names of each month, including leap months as needed. Characters indicated whether a month was short; the traditional Chinese calendar was developed between 771 and 476 BC, during the Spring and Autumn period of the Eastern Zhou dynasty. Before the Zhou dynasty, solar calendars were used. One version of the solar calendar is the five-elements calendar. A 365-day year was divided into five phases of 73 days, with each phase corresponding to a Day 1 Wu Xing element.
A phase began followed by six 12-day weeks. Each phase consisted of two three-week months. Years began followed by a bǐngzǐ day and a 72-day fire phase. Other days were tracked using the Yellow River Map. Another version is a four-quarters calendar. Weeks were ten days long, with one month consisting of three weeks. A year had 12 months, with a ten-day week intercalated in summer as needed to keep up with the tropical year; the 10 Heavenly Stems and 12 Earthly Branches were used to mark days. A third version is the balanced calendar. A year was 365.25 days, a month was 29.5 days. After every 16th month, a half-month was intercalated. According to oracle bone records, the Shang dynasty calendar was a balanced calendar with 12 to 14 months in a year; the first lunisolar calendar was the Zhou calendar, introduced under the Zhou dynasty. This calendar set the beginning of the year at the day of the new moon before the winter solstice, it set the shàngyuán as the winter solstice of a dīngsì year, making the year it was introduced around 2,758,130.
Several competing lunisolar calendars were introduced by states fighting Zhou control during the Warring States period. The state of Lu issued its own Lu calendar. Jin issued the Xia calendar in AD 102, with a year beginning on the day of the new moon nearest the March equinox. Qin issued the Zhuanxu calendar, with a year beginning on the day of the new moon nearest the winter solstice. Song's Yin calendar began its year on the day of the new moon after the winter solstice; these calendars are known as the six ancient calendars, or quarter-remainder calendars, since all calculate a year as 365 1⁄4 days long. Months begin on the day of the new moon, a year has 12 or 13 months. Intercalary months are added to the end of the year; the Qiang and Dai calendars are modern versions of the Zhuanxu calendar, used by mountain peoples. After Qin Shi Huang unified China under the Qin dynasty in 221 BC, the Qin calendar was introduced, it followed most of the rules governing the Zhuanxu calendar, but the month order was that of the Xia calendar.
The intercalary month, known as the second Jiǔyuè, was placed at the end of the year. The Qin calendar was used into the Han dynasty. Emperor Wu of Han r. 141 – 87 BC introduced reforms halfway through his reign. His Taichu Calendar defined a solar year as 365 385⁄1539 days, the lunar month was 29 43⁄81 days; this calendar introduced the 24 solar terms. Solar terms were paired, with the 12 combined periods known as climate terms; the first solar term of the period was known as a pre-climate, the second was a mid-climate. Months were named for the mid-climat
The Buddhist calendar is a set of lunisolar calendars used in mainland Southeast Asian countries of Cambodia, Laos and Thailand as well as in Sri Lanka and Chinese populations of Malaysia and Singapore for religious or official occasions. While the calendars share a common lineage, they have minor but important variations such as intercalation schedules, month names and numbering, use of cycles, etc. In Thailand, the name Buddhist Era is a year numbering system shared by the traditional Thai lunisolar calendar and by the Thai solar calendar; the Southeast Asian lunisolar calendars are based on an older version of the Hindu calendar, which uses the sidereal year as the solar year. One major difference is that the Southeast Asian systems, unlike their Indian cousins, do not use apparent reckoning to stay in sync with the sidereal year. Instead, they employ their versions of the Metonic cycle. However, since the Metonic cycle is not accurate for sidereal years, the Southeast Asian calendar is drifting out of sync with the sidereal one day every 100 years.
Yet no coordinated structural reforms of the lunisolar calendar have been undertaken. Today, the traditional Buddhist lunisolar calendar is used for Theravada Buddhist festivals, no longer has the official calendar status anywhere; the Thai Buddhist Era, a renumbered Gregorian calendar, is the official calendar in Thailand. The calculation methodology of the current versions of Southeast Asian Buddhist calendars is based on that of the Burmese calendar, in use in various Southeast Asian kingdoms down to the 19th century under the names of Chula Sakarat and Jolak Sakaraj; the Burmese calendar in turn was based on the "original" Surya Siddhanta system of ancient India. One key difference with Indian systems is that the Burmese system has followed a variation of the Metonic cycle, it is unclear from where, how the Metonic system was introduced. The Burmese system, indeed the Southeast Asian systems, thus use a "strange" combination of sidereal years from Indian calendar in combination with the Metonic cycle better for tropical years.
In all Theravada traditions, the calendar's epochal year 0 date was the day in which the Buddha attained parinibbāna. However, not all traditions agree on when it took place. In Burmese Buddhist tradition, it was 13 May 544 BCE, but in Thailand, it was 11 March 545 BCE, the date which the current Thai lunisolar and solar calendars use as the epochal date. Yet, the Thai calendars for some reason have fixed the difference between their Buddhist Era numbering and the Christian/Common Era numbering at 543, which points to an epochal year of 544 BCE, not 545 BCE. In Myanmar, the difference between BE and CE can be 543 or 544 for CE dates, 544 or 543 for BCE dates, depending on the month of the Buddhist Era. In Sri Lanka, the difference between BE and CE is 544; the calendar recognizes two types of months: sidereal month. The Synodic months are used to compose the years while the 27 lunar sidereal days, alongside the 12 signs of the zodiac, are used for astrological calculations; the days of the month are counted in two halves and waning.
The 15th of the waxing is the civil full moon day. The civil new moon day is the last day of the month; because of the inaccuracy of the calendrical calculation systems, the mean and real New Moons coincide. The mean New Moon precedes the real New Moon; as the Synodic lunar month is 29.5 days, the calendar uses alternating months of 29 and 30 days. Various regional versions of Chula Sakarat/Burmese calendar existed across various regions of mainland Southeast Asia. Unlike Burmese systems, Lan Na, Lan Xang and Sukhothai systems refer to the months by numbers, not by names; this means reading ancient texts and inscriptions in Thailand requires constant vigilance, not just in making sure one is operating for the correct region, but for variations within regions itself when incursions cause a variation in practice. However, Cambodian month system, which begins with Margasirsa as the first month, demonstrated by the names and numbers; the Buddhist calendar is a lunisolar calendar in which the months are based on lunar months and years are based on solar years.
One of its primary objectives is to synchronize the lunar part with the solar part. The lunar months twelve of them, consist alternately of 29 days and 30 days, such that a normal lunar year will contain 354 days, as opposed to the solar year of ~365.25 days. Therefore, some form of addition to the lunar year is necessary; the overall basis for it is provided by cycles of 57 years. Eleven extra days are inserted in every 57 years, seven extra months of 30 days are inserted in every 19 years; this provides 20819 complete days to both calendars. This 57-year cycle would provide a mean year of about 365.2456 days and a mean month of about 29.530496 days, if not corrected. As such, the calendar adds an intercalary month in leap years and sometimes an intercalary day in great leap years; the intercalary month not only corrects the length of the year but corrects the accumulating error of the month to extent of half a day. The average length of the month is further corrected by adding a day to Nayon
The Islamic, Muslim, or Hijri calendar is a lunar calendar consisting of 12 lunar months in a year of 354 or 355 days. It is used to determine the proper days of Islamic holidays and rituals, such as the annual period of fasting and the proper time for the pilgrimage to Mecca; the civil calendar of all countries where the religion is predominantly Muslim is the Gregorian calendar. Notable exceptions to this rule are Afghanistan, which use the Solar Hijri calendar. Rents and similar regular commitments are paid by the civil calendar; the Islamic calendar employs the Hijri era whose epoch was established as the Islamic New Year of 622 AD/CE. During that year and his followers migrated from Mecca to Yathrib and established the first Muslim community, an event commemorated as the Hijra. In the West, dates in this era are denoted AH in parallel with the Christian and Jewish eras. In Muslim countries, it is sometimes denoted as H from its Arabic form. In English, years prior to the Hijra are reckoned as BH.
The current Islamic year is 1440 AH. In the Gregorian calendar, 1440 AH runs from 11 September 2018 to 30 August 2019. For central Arabia Mecca, there is a lack of epigraphical evidence but details are found in the writings of Muslim authors of the Abbasid era. Inscriptions of the ancient South Arabian calendars reveal the use of a number of local calendars. At least some of these South Arabian calendars followed the lunisolar system. Both al-Biruni and al-Mas'udi suggest that the ancient Arabs used the same month names as the Muslims, though they record other month names used by the pre-Islamic Arabs; the Islamic tradition is unanimous in stating that Arabs of Tihamah and Najd distinguished between two types of months and forbidden months. The forbidden months were four months during which fighting is forbidden, listed as Rajab and the three months around the pilgrimage season, Dhu al-Qa‘dah, Dhu al-Hijjah, Muharram. Information about the forbidden months is found in the writings of Procopius, where he describes an armistice with the Eastern Arabs of the Lakhmid al-Mundhir which happened in the summer of 541 AD/CE.
However, Muslim historians do not link these months to a particular season. The Qur'an links the four forbidden months with Nasī’, a word that means "postponement". According to Muslim tradition, the decision of postponement was administered by the tribe of Kinanah, by a man known as the al-Qalammas of Kinanah and his descendants. Different interpretations of the concept of Nasī’ have been proposed; some scholars, both Muslim and Western, maintain that the pre-Islamic calendar used in central Arabia was a purely lunar calendar similar to the modern Islamic calendar. According to this view, Nasī’ is related to the pre-Islamic practices of the Meccan Arabs, where they would alter the distribution of the forbidden months within a given year without implying a calendar manipulation; this interpretation is supported by Arab historians and lexicographers, like Ibn Hisham, Ibn Manzur, the corpus of Qur'anic exegesis. This is corroborated by an early Sabaic inscription, where a religious ritual was "postponed" due to war.
According to the context of this inscription, the verb ns'’ has nothing to do with intercalation, but only with moving religious events within the calendar itself. The similarity between the religious concept of this ancient inscription and the Qur'an suggests that non-calendaring postponement is the Qur'anic meaning of Nasī’; the Encyclopaedia of Islam concludes "The Arabic system of can only have been intended to move the Hajj and the fairs associated with it in the vicinity of Mecca to a suitable season of the year. It was not intended to establish a fixed calendar to be observed." The term "fixed calendar" is understood to refer to the non-intercalated calendar. Others concur that it was a lunar calendar, but suggest that about 200 years before the Hijra it was transformed into a lunisolar calendar containing an intercalary month added from time to time to keep the pilgrimage within the season of the year when merchandise was most abundant; this interpretation was first proposed by the medieval Muslim astrologer and astronomer Abu Ma'shar al-Balkhi, by al-Biruni, al-Mas'udi, some western scholars.
This interpretation considers Nasī’ to be a synonym to the Arabic word for "intercalation". The Arabs, according to one explanation mentioned by Abu Ma'shar, learned of this type of intercalation from the Jews; the Jewish Nasi was the official. Some sources say that the Arabs followed the Jewish practice and intercalated seven months over nineteen years, or else that they intercalated nine months over 24 years. Postponement of one ritual in a particular circumstance does not imply alteration of the sequence of months, scholars agree that this did not happen. Al-Biruni says this did not happen, the festivals were kept within their season by intercalation every second or third year of a month between Dhu al-Hijjah and Muharram, he says that, in terms of the fixed calendar, not introduced until 10 AH, the first intercalation was, for example, of a month between Dhu al-Hijjah and Muharram, the second of a month between Muharram and Safar, the third of a month between Safar and Rabi'I, so on. The intercalations were arranged.
The notice of interca