The Byzantine Empire referred to as the Eastern Roman Empire or Byzantium, was the continuation of the Roman Empire in its eastern provinces during Late Antiquity and the Middle Ages, when its capital city was Constantinople. It survived the fragmentation and fall of the Western Roman Empire in the 5th century AD and continued to exist for an additional thousand years until it fell to the Ottoman Turks in 1453. During most of its existence, the empire was the most powerful economic and military force in Europe. Both the terms "Byzantine Empire" and "Eastern Roman Empire" are historiographical terms created after the end of the realm. Several signal events from the 4th to 6th centuries mark the period of transition during which the Roman Empire's Greek East and Latin West diverged. Constantine I reorganised the empire, made Constantinople the new capital, legalised Christianity. Under Theodosius I, Christianity became the Empire's official state religion and other religious practices were proscribed.
Under the reign of Heraclius, the Empire's military and administration were restructured and adopted Greek for official use in place of Latin. Thus, although the Roman state continued and its traditions were maintained, modern historians distinguish Byzantium from ancient Rome insofar as it was centred on Constantinople, oriented towards Greek rather than Latin culture, characterised by Eastern Orthodox Christianity; the borders of the empire evolved over its existence, as it went through several cycles of decline and recovery. During the reign of Justinian I, the empire reached its greatest extent after reconquering much of the Roman western Mediterranean coast, including North Africa and Rome itself, which it held for two more centuries; the Byzantine–Sasanian War of 602–628 exhausted the empire's resources and contributed to major territorial losses during the Early Muslim conquests of the 7th century, when it lost its richest provinces and Syria, to the Arab caliphate. During the Macedonian dynasty, the empire expanded again and experienced the two-century long Macedonian Renaissance, which came to an end with the loss of much of Asia Minor to the Seljuk Turks after the Battle of Manzikert in 1071.
This battle opened the way for the Turks to settle in Anatolia. The empire recovered during the Komnenian restoration, by the 12th century Constantinople was the largest and wealthiest European city. However, it was delivered a mortal blow during the Fourth Crusade, when Constantinople was sacked in 1204 and the territories that the empire governed were divided into competing Byzantine Greek and Latin realms. Despite the eventual recovery of Constantinople in 1261, the Byzantine Empire remained only one of several small rival states in the area for the final two centuries of its existence, its remaining territories were progressively annexed by the Ottomans over the 15th century. The Fall of Constantinople to the Ottoman Empire in 1453 ended the Byzantine Empire; the last of the imperial Byzantine successor states, the Empire of Trebizond, would be conquered by the Ottomans eight years in the 1461 Siege of Trebizond. The first use of the term "Byzantine" to label the years of the Roman Empire was in 1557, when the German historian Hieronymus Wolf published his work Corpus Historiæ Byzantinæ, a collection of historical sources.
The term comes from "Byzantium", the name of the city of Constantinople before it became Constantine's capital. This older name of the city would be used from this point onward except in historical or poetic contexts; the publication in 1648 of the Byzantine du Louvre, in 1680 of Du Cange's Historia Byzantina further popularised the use of "Byzantine" among French authors, such as Montesquieu. However, it was not until the mid-19th century that the term came into general use in the Western world; the Byzantine Empire was known to its inhabitants as the "Roman Empire", the "Empire of the Romans", "Romania", the "Roman Republic", as "Rhōmais". The inhabitants called themselves Romaioi and as late as the 19th century Greeks referred to Modern Greek as Romaiika "Romaic." After 1204 when the Byzantine Empire was confined to its purely Greek provinces the term'Hellenes' was used instead. While the Byzantine Empire had a multi-ethnic character during most of its history and preserved Romano-Hellenistic traditions, it became identified by its western and northern contemporaries with its predominant Greek element.
The occasional use of the term "Empire of the Greeks" in the West to refer to the Eastern Roman Empire and of the Byzantine Emperor as Imperator Graecorum were used to separate it from the prestige of the Roman Empire within the new kingdoms of the West. No such distinction existed in the Islamic and Slavic worlds, where the Empire was more straightforwardly seen as the continuation of the Roman Empire. In the Islamic world, the Roman Empire was known as Rûm; the name millet-i Rûm, or "Roman nation," was used by the Ottomans through the 20th century to refer to the former subjects of the Byzantine Empire
The Republic of China calendar is the official calendar of the Republic of China. It is used to number the years for official purposes only in the Taiwan area after 1949, it was used in the Chinese mainland from 1912 until the establishment of the People's Republic of China in 1949. Following the Chinese imperial tradition of using the sovereign's era name and year of reign, official ROC documents use the Republic system of numbering years in which the first year was 1912, the year of the establishment of the Republic of China. Months and days are numbered according to the Gregorian calendar; the Gregorian calendar was adopted by the nascent Republic of China effective 1 January 1912 for official business, but the general populace continued to use the traditional Chinese calendar. The status of the Gregorian calendar was unclear between 1916 and 1921 while China was controlled by several competing warlords each supported by foreign colonial powers. From about 1921 until 1928 warlords continued to fight over northern China, but the Kuomintang or Nationalist government controlled southern China and used the Gregorian calendar.
After the Kuomintang reconstituted the Republic of China on 10 October 1928, the Gregorian calendar was adopted, effective 1 January 1929. The People's Republic of China has continued to use the Gregorian calendar since 1949. Despite the adoption of the Gregorian calendar, the numbering of the years was still an issue; the Chinese imperial tradition was to use the emperor's era year of reign. One alternative to this approach was to use the reign of the half-historical, half-legendary Yellow Emperor in the third millennium BC to number the years. In the early 20th century, some Chinese Republicans began to advocate such a system of continuously numbered years, so that year markings would be independent of the Emperor's regnal name; when Sun Yat-sen became the provisional president of the Republic of China, he sent telegrams to leaders of all provinces and announced the 13th day of 11th Month of the 4609th year of the Yellow Emperor's reign to be the first year of the Republic of China. The original intention of the Minguo calendar was to follow the imperial practice of naming the years according to the number of years the Emperor had reigned, a universally recognizable event in China.
Following the establishment of the Republic, hence the lack of an Emperor, it was decided to use the year of the establishment of the current regime. This reduced the issue of frequent change in the calendar, as no Emperor ruled more than 61 years in Chinese history — the longest being the Kangxi Emperor, who ruled from 1662–1722; as Chinese era names are traditionally two characters long, 民國 is employed as an abbreviation of 中華民國. The first year, 1912, is called 民國元年 and 2010, the "99th year of the Republic" is 民國九十九年, 民國99年, or 99. Based on Chinese National Standard CNS 7648: Data Elements and Interchange Formats—Information Interchange—Representation of Dates and Times, year numbering may use the Gregorian system as well as the ROC era. For example, 3 May 2004 may be written 2004-05-03 or ROC 93-05-03; the ROC era numbering happens to be the same as the numbering used by the Juche calendar of North Korea, because its founder, Kim Il-sung, was born in 1912. The years in Japan's Taishō period coincide with those of the ROC era.
In addition to the ROC's Minguo calendar, Taiwanese continue to use the lunar Chinese calendar for certain functions such as the dates of many holidays, the calculation of people's ages, religious functions. The use of the ROC era system extends beyond official documents. Misinterpretation is more in the cases when the prefix is omitted. There have been legislative proposals by pro-Taiwan Independence political parties, such as the Democratic Progressive Party to abolish the Republican calendar in favor of the Gregorian calendar. To convert any Gregorian calendar year between 1912 and the current year to Minguo calendar, 1912 needs to be subtracted from the year in question 1 added. East Asian age reckoning Public holidays in Taiwan
Indian national calendar
The Indian national calendar, sometimes called the Shalivahana Shaka calendar. It is used, alongside the Gregorian calendar, by The Gazette of India, in news broadcasts by All India Radio and in calendars and communications issued by the Government of India; the Saka calendar is used in Java and Bali among Indonesian Hindus. Nyepi, the "Day of Silence", is a celebration of the Saka new year in Bali. Nepal's Nepal Sambat evolved from the Saka calendar. Prior to colonization, the Philippines used to apply the Saka calendar as well as suggested by the Laguna Copperplate Inscription; the term may ambiguously refer to the Hindu calendar. The historic Shalivahana era calendar is still used, it has years. The calendar months follow the signs of the tropical zodiac rather than the sidereal zodiac used with the Hindu calendar. Chaitra has 30 days and starts on March 22, except in leap years, when it has 31 days and starts on March 21; the months in the first half of the year all have 31 days, to take into account the slower movement of the sun across the ecliptic at this time.
The names of the months are derived from older, Hindu lunisolar calendars, so variations in spelling exist, there is a possible source of confusion as to what calendar a date belongs to. Years are counted in the Saka era. To determine leap years, add 78 to the Saka year – if the result is a leap year in the Gregorian calendar the Saka year is a leap year as well, its structure is just like the Persian calendar. Senior Indian Astrophysicist Meghnad Saha was the head of the Calendar Reform Committee under the aegis of the Council of Scientific and Industrial Research. Other members of the Committee were: A. C. Banerjee, K. K. Daftari, J. S. Karandikar, Gorakh Prasad, R. V. Vaidya and N. C. Lahiri, it was Saha's effort. The task before the Committee was to prepare an accurate calendar based on scientific study, which could be adopted uniformly throughout India, it was a mammoth task. The Committee had to undertake a detailed study of different calendars prevalent in different parts of the country. There were thirty different calendars.
The task was further complicated by the fact that religion and local sentiments were integral to those calendars. India's first prime minister, Jawaharlal Nehru, in his preface to the Report of the Committee, published in 1955, wrote: “They represent past political divisions in the country.... Now that we have attained Independence, it is desirable that there should be a certain uniformity in the calendar for our civic and other purposes, this should be done on a scientific approach to this problem.” Usage started at 1 Chaitra 1879, Saka Era, or 22 March 1957. Report of the Calendar Reform Committee – online link. Mapping Time: The Calendar and its History by E. G. Richards, 1998, pp. 184–185. Calendars and their History Indian Calendars Positional astronomy in India Indian National Calendar abstract
Kali Yuga in Hinduism is the last of the four stages the world goes through as part of a'cycle of yugas' described in the Sanskrit scriptures. The other ages are called Satya Yuga, Treta Yuga, Dvapara Yuga. Kali Yuga is associated with the demon Kali; the "Kali" of Kali Yuga means "strife", "discord", "quarrel" or "contention". According to Puranic sources, Krishna's departure marks the end of Dvapara Yuga and the start of Kali Yuga, dated to 17/18 February 3102 BCE. According to the Surya Siddhanta, Kali Yuga began at midnight on 18 February 3102 BCE; this is considered the date on which Lord Krishna left the earth to return to Vaikuntha. This information is placed at the temple of the place of this incident. According to the astronomer and mathematician Aryabhatta the Kali Yuga started in 3102 BCE, he finished his book "Aryabhattiya" in 499 CE, in which he gives the exact year of the beginning of Kali Yuga. He writes that he wrote the book in the "year 3600 of the Kali Age" at the age of 23; as it was the 3600th year of the Kali Age when he was 23 years old, given that Aryabhatta was born in 476 CE, the beginning of the Kali Yuga would come to 3102 BCE.
According to KD Abhyankar, the starting point of Kali Yuga is an rare planetary alignment, depicted in the Mohenjo-Daro seals. Going by this alignment the year 3102 BCE is off; the actual date for this alignment is 7 February of 3104 BCE. There is sufficient proof to believe that Vrdhha Garga knew of precession at least by 500 BCE. Garga had calculated the rate of precession to within 30 % of; the common belief until Swami Sri Yukteswar Giri had analyzed the dating of the Yuga cycles was that the Kali Yuga would last for 432,000 years after the end of the Dwapara Yuga. This originated during the puranic times when the famous astronomer Aryabhatta recalculated the timeline by artificially inflating the traditional 12,000 year figure with a multiplication of 360, represented as the number of "human years" that make up a single "divine year"; this was a purposeful miscalculation due to conflicts with one of the preeminent astronomer of the time Brahmagupta. However, both the Mahabharata and the Manu Smriti have the original value of 12,000 years for one half of the Yuga cycle.
Contemporary analysis of historical data from the last 11 millennia matches with the indigenous Saptarishi Calendar. The length of the transitional periods between each Yuga is unclear, can only be estimated based on historical data of past cataclysmic events. Using a 300 year period for transitions, Kali Yuga has either ended in the past 100 to 200 years, or is to end soon sometime in the next 100 years. Other authors, such as the revered Hindu guru Swami Sri Yukteswar in his book The Holy Science, as well as the influential Yogi Paramhansa Yogananda, believe that the Kali Yuga has ended, that we are now in an ascending Dvapara Yuga; this calculation is supported by modern day spiritual masters such as Sadhguru Jaggi Vasudev. Hindus believe that human civilization degenerates spiritually during the Kali Yuga, referred to as the Dark Age because in it people are as far away as possible from God. Hinduism symbolically represents morality as an Indian bull. Common attributes and consequences are spiritual bankruptcy, mindless hedonism, breakdown of all social structure and materialism, unrestricted egotism and maladies of mind and body.
In Satya Yuga, the first stage of development, the bull has four legs, but in each age morality is reduced by one quarter. By the age of Kali, morality is reduced to only a quarter of that of the golden age, so that the bull of Dharma has only one leg; the Mahabharata War and the decimation of Kauravas thus happened at the "Yuga-Sandhi", the point of transition from one yuga to another. The scriptures mention Sage Narada to have momentarily intercepted the demon Kali on his way to the Earth when Duryodhana was about to be born in order to make him an embodiment of arishadvargas and adharma in preparation of the era of decay in values and the consequent havoc. A discourse by Markandeya in the Mahabharata identifies some of the attributes of Kali Yuga. In relation to rulers, it lists: Rulers will become unreasonable: they will levy taxes unfairly. Rulers will no longer see it as their duty to promote spirituality, or to protect their subjects: they will become a danger to the world. People will start seeking countries where wheat and barley form the staple food source.
"At the end of Kali-yuga, when there exist no topics on the subject of God at the residences of so-called saints and respectable gentlemen of the three higher varnas and when nothing is known of the techniques of sacrifice by word, at that time the Lord will appear as the supreme chastiser." (Srimad-Bhagavatam With regard to human relationships, Markandeya's discourse says: Avarice and wrath will be common. Humans will display animosity towards each other. Ignorance of dharma will occur. People will see nothing wrong in that. Lust will be viewed as acceptable and sexual intercourse will be seen as the central requirement of life. Sin will increase exponentially, while virtue will cease to flourish. People will become addicted to intoxicating drugs. Gurus will no longer be respected and their students will attempt
Simeon I of Bulgaria
Simeon I the Great ruled over Bulgaria from 893 to 927, during the First Bulgarian Empire. Simeon's successful campaigns against the Byzantines and Serbs led Bulgaria to its greatest territorial expansion making it the most powerful state in contemporary Eastern Europe, his reign was a period of unmatched cultural prosperity and enlightenment deemed the Golden Age of Bulgarian culture. During Simeon's rule, Bulgaria spread over a territory between the Aegean, the Adriatic and the Black Sea; the newly independent Bulgarian Orthodox Church became the first new patriarchate besides the Pentarchy, Bulgarian Glagolitic and Cyrillic translations of Christian texts spread all over the Slavic world of the time. It was at the Preslav Literary School in the 890s. Halfway through his reign, Simeon assumed the title of Emperor, having prior to that been styled Prince. Simeon was born as the third son of Knyaz Boris I of Krum's dynasty; as Boris was the ruler who Christianized Bulgaria in 865, Simeon was a Christian all his life.
Because his eldest brother Vladimir was designated heir to the Bulgarian throne, Boris intended Simeon to become a high-ranking cleric Bulgarian archbishop, sent him to the leading University of Constantinople to receive theological education when he was thirteen or fourteen. He took the name Simeon as a novice in a monastery in Constantinople. During the decade he spent in the Byzantine capital, he received excellent education and studied the rhetoric of Demosthenes and Aristotle, he learned fluent Greek, to the extent that he was referred to as "the half-Greek" in Byzantine chronicles. He is speculated to have been tutored by Patriarch Photios I of Constantinople, but this is not supported by any source. Around 888, Simeon returned to Bulgaria and settled at the newly established royal monastery of Preslav "at the mouth of the Tiča", under the guidance of Naum of Preslav, he engaged in active translation of important religious works from Greek to Medieval Bulgarian, aided by other students from Constantinople.
Meanwhile, Vladimir had succeeded Boris, who had retreated as ruler of Bulgaria. Vladimir attempted to reintroduce paganism in the empire and signed an anti-Byzantine pact with Arnulf of Carinthia, forcing Boris to re-enter political life. Boris had Vladimir imprisoned and blinded, appointed Simeon as the new ruler; this was done at an assembly in Preslav which proclaimed Bulgarian as the only language of state and church and moved the Bulgarian capital from Pliska to Preslav, to better cement the recent conversion. It is not known why Boris did not place his second son, Gavril, on the throne, but instead preferred Simeon. With Simeon on the throne, the long-lasting peace with the Byzantine Empire established by his father was about to end. A conflict arose when Byzantine Emperor Leo VI the Wise acting under pressure from his mistress Zoe Zaoutzaina and her father Stylianos Zaoutzes, moved the marketplace for Bulgarian goods from Constantinople to Thessaloniki, where the Bulgarian merchants were taxed.
The Bulgarians sought protection by Simeon. However, the Byzantine emperor ignored his embassy. Forced to take action, in the autumn of 894 Simeon invaded the Byzantine Empire from the north, meeting with little opposition due to the concentration of most Byzantine forces in eastern Anatolia to counter Arab invasions. Informed of the Bulgarian offensive, the surprised Leo sent an army consisting of guardsmen and other military units from the capital to halt Simeon, but his troops were routed somewhere in the theme of Macedonia; the Bulgarians took most of the Khazar mercenary guardsmen prisoners and killed many archons, including the army's commander. However, instead of continuing his advance to the Byzantine capital, Simeon withdrew his troops to face a Magyar invasion from the north; these events were called "the first trade war in medieval Europe" by Bulgarian historians. Unable to respond to the Bulgarian campaign due to the engagement of their forces against the Arabs, the Byzantines convinced the Magyars to attack Bulgaria, promising to transport them across the Danube using the Byzantine navy.
Leo VI may have concluded an agreement with Arnulf to make sure that the Franks did not support Simeon against the Magyars. In addition, the talented commander Nikephoros Phokas was called back from southern Italy to lead a separate army against Bulgaria in 895 with the mere intention to overawe the Bulgarians. Simeon, unaware of the threat from the north, rushed to meet Phokas' forces, but the two armies did not engage in a fight. Instead, the Byzantines offered peace, informing him of both the Byzantine foot and maritime campaign, but intentionally did not notify him of the planned Magyar attack. Simeon did not trust the envoy and, after sending him to prison, ordered the Byzantine navy's route into the Danube closed off with ropes and chains, intending to hold it until he had dealt with Phokas. Despite the problems they encountered because of the fencing, the Byzantines managed to ferry the Magyar forces led by Árpád's son Liüntika across the Danube near modern Galaţi, assisted them in pillaging the nearby Bulgarian lands.
Once notified of the surprise invasion, Simeon headed north to stop the Magyars, leaving some of his troops at the southern border to prevent a possible attack by Phokas. Simeon's two encounters with the enemy in Northern Dobruja resulted in Magyar victories, forcing him to retreat to Drǎstǎr. After pillaging much of Bulgaria and
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
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