5th century BC
The 5th century BC started the first day of 500 BC and ended the last day of 401 BC. This century saw the establishment of Pataliputra as a capital of the Magadha Empire; this city would become the ruling capital of different Indian kingdoms for about a thousand years. This period saw the rise of two great philosophical schools of the east and Buddhism; this period saw Mahavira and Buddha spreading their respective teachings in the northern plains of India. This changed the socio-cultural and political dynamics of the region of South Asia. Buddhism would go on to become one of the major world religions; this period saw the work of Yaska, who created Nirukta, that would lay the foundation stone for Sanskrit grammar and is one of the oldest works on grammar known to mankind. This century is traditionally recognized as the classical period of the Greeks, which would continue all the way through the 4th century until the time of Alexander the Great; the life of Socrates represented a major milestone in Greek philosophy though his teachings only survive through the work of his students, most notably Plato and Xenophon.
The tragedians Aeschylus and Euripides, as well as the comedian Aristophanes all date from this era and many of their works are still considered classics of the western theatrical canon. The Persian Wars, fought between a coalition of Greek cities and the vast Achaemenid Persian Empire was a pivotal moment in Greek politics. After having prevented the annexation of Greece by the Persians, the dominant power in the coalition, had no intention of further offensive action and considered the war over. Meanwhile, Athens counter-attacked, liberating Greek subjects of the Persian Empire up and down the Ionian coast and mobilizing a new coalition, the Delian League. Tensions between Athens, its growing imperialistic ambitions as leader of the Delian League, the traditionally dominant Sparta led to a protracted stalemate in the Peloponnesian war. Demotic becomes the dominant script of ancient Egypt. 499 BC: Aristagoras, acting on behalf of the Persian Empire, leads a failed attack on the rebellious island of Naxos.
499 BC: Aristagoras instigates the Ionian Revolt, beginning the Persian Wars between Greece and Persia. 499 BC: Sardis sacked by Athenian and Ionian troops. 498 BC: Leontini subjugated by Hippocrates of Gela. 498 BC: Alexander I succeeds his father Amyntas I as king of Macedon. 496 BC: Battle of Lake Regillus: A legendary early Roman victory, won over either the Etruscans or the Latins. 496 BC: Sophocles is born. 495 BC: Temple to Mercury on the Circus Maximus in Rome is built. 494 BC: The Battle of Lade, where Persians take back Ionia. 494 BC: Two tribunes of the plebs and two plebeian aediles are elected for the first time in Rome: the office of the tribunate is established. 494 BC: The year Rome changed from an Aristocratic Republic to a Liberalized Republic. 493 BC: Piraeus, the port town of Athens, is founded. 493 BC: Coriolanus captures the Volscian town of Corioli for Rome. 492 BC: First expedition of King Darius I of Persia against Greece, under the leadership of his son-in-law Mardonius. This marks the start of the campaign that culminated in the Battle of Marathon in 490 BC. 491 BC: Leotychidas succeeds his cousin Demaratus as king of Sparta.
491 BC: Gelo becomes Tyrant of Gela. 490 BC: The Battle of Marathon, where Darius I of Persia is defeated by the Athenians and Plataeans under Miltiades 490 BC: Phidippides runs 40 kilometers from Marathon to Athens to announce the news of the Greek victory. 489 BC: Cities of Rhodes unite and start construction of the new city of Rhodes. 488 BC: Leonidas I succeeds his brother Cleomenes I as king of Sparta after Cleomenes is judged insane. 487 BC: Egypt revolts against the Persians. 487 BC: Aegina and Athens go to war. 487 BC: Athenian Archonship becomes elective by lot, an important milestone in the move towards radical Athenian democracy. 486 BC: First part of the Grand Canal of China is built. 486 BC: Xerxes I succeeds Darius I as Great King of Persia. 486 BC: Egypt revolts against Persian rule. 486 BC: First Buddhist Council at Rejgaha, under the patronage of King Ajatasattu. Oral tradition established for the first time. 484 BC: Athenian playwright Aeschylus wins a poetry prize. 484 BC: Xerxes I abolishes the Kingdom of Babel and removes the golden statue of Bel.
484 BC: Persians regain control of Egypt. 483 BC: Gautama Buddha dies. 483 BC: Xerxes I of Persia starts planning his expedition against Greece 481 BC: The Isthmus of Corinth ends a war between Athens and Aegina. 480 BC: King Xerxes I of Persia sets out to conquer Greece. 480 BC: Cimon and his friends burn horse-bridles as an offering to Athena and join the marines 480 BC: Pleistarchus succeeds his father Leonidas I as king of Sparta. August, 480 BC: Battle of Artemisium—The Persian fleet fights an inconclusive battle with the Greek allied fleet. August 11, 480 BC: The Battle of Thermopylae, a costly victory by Persians over the Greeks. September 23, 480 BC: Battle of Salamis between Greece and Persia, leading to a Greek victory. 480 BC: Battle of Himera—The Carthaginians under Hamilcar are defeated by the Greeks of Sicily, led by Gelon of Syracuse. 480 BC: Roman troops march against the Veientines. 479 BC: The Battle of Plataea, the Greeks defeat the Persians, ending the Persian Wars. 479 BC: Battle of Mycale.
479 BC: Potidaea is struck by a tsunami. 479 BC: Chinese philosopher Confucius dies. 478 BC: Establishment of the Temple of Confucius at Qufu. 477 BC: The Delian League is inaugurated. 476 BC: Archidamus II succeeds his grandfather Leotychides, banished to Tegea, as king of Sparta. 475 BC: King Xuan of Zhou becomes King of the Zhou Dynasty. 474 BC: Battle of Cumae—The Syracusans under Hiero
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 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 Javanese calendar is the calendar of the Javanese people. It is used concurrently with the Gregorian calendar and the Islamic calendar; the Gregorian calendar is the official calendar of the Republic of Indonesia and civil society, while the Islamic calendar is used by Muslims and the Indonesian government for religious worship and deciding relevant Islamic holidays. The Javanese calendar is used by the main ethnicities of Java island—that is, the Javanese and Sundanese people—primarily as a cultural icon and identifier, as a maintained tradition of antiquity; the Javanese calendar is used for cultural and spiritual purposes. The current system of the Javanese calendar was inaugurated by Sultan Agung of Mataram in the Gregorian year 1633 CE. Prior to this, the Javanese had used the Hindu calendar, which begins in 78 CE and uses the solar cycle for calculating time. Sultan Agung's calendar retained the Saka calendar year system of counting, but differs by using the same lunar year measurement system as the Islamic calendar, rather than the solar year.
The Javanese calendar is referred to by its Latin name Anno Javanico or AJ. The Javanese calendar contains multiple, overlapping measurements of times, called "cycles"; these include: the native five-day week, called Pasaran the common Gregorian and Islamic seven-day week the Solar month, called Mangsa the Lunar month, called Wulan the lunar year, or Tahun the octo-ennia cycles, or Windu the 120-year cycle of 15 Windu, called Kurup Days in the Javanese calendar, like the Islamic calendar, begin at sunset. Traditionally, Javanese people do not divide the night into hours, but rather into phases; the division of a day and night are: The native Javanese system groups days into a five-day week called Pasaran, unlike most calendars that uses a seven-day week. The name, pasaran, is derived from the root word pasar, but still today, Javanese villagers gather communally at local markets to meet, engage in commerce, buy and sell farm produce, cooked foods, home industry crafted items and so on. John Crawfurd suggested that the length of the weekly cycle is related to the number of fingers on the hand, that itinerant merchants would rotate their visits to different villages according to a five-day "roster".
The days of the cycle each have two names, as the Javanese language has distinct vocabulary associated with two different registers of politeness: ngoko and krama. The krama names for the days, second in the list, are much less common. ꦊꦒꦶ – ꦩꦤꦶꦱ꧀ ꦥꦲꦶꦁ – ꦥꦲꦶꦠ꧀ ꦥꦺꦴꦤ꧀ – ꦥꦼꦠꦏ꧀ ꦮꦒꦺ – ꦕꦼꦩꦺꦁ ꦏ꧀ꦭꦶꦮꦺꦴꦤ꧀ – ꦲꦱꦶꦃ The origin of the names is unclear, their etymology remains obscure. The names may be derived from indigenous gods, like the European and Asian names for days of the week. An ancient Javanese manuscript illustrates the week with five human figures: a man seizing a suppliant by the hair, a woman holding a horn to receive an offering, a man pointing a drawn sword at another, a woman holding agricultural produce, a man holding a spear leading a bull. Additionally, Javanese consider these days' names to have a mystical relation to colors and cardinal direction: Legi: white and East Pahing: red and South Pon: yellow and West Wage: black and North Kliwon: blurred colors/focus and'center'. Most Markets no longer operate under this traditional Pasaran cycle, instead pragmatically remaining open every day of the Gregorian week.
However many markets in Java still retain traditional names that indicated that once the markets only operated on certain Pasaran days, such as Pasar Legi, or Pasar Kliwon. Some markets in small or medium size locations will be much busier on the Pasaran day than on the other days. On the market's name day itinerate sellers appear selling such things as livestock and other products that are either less purchased or are more expensive; this allows a smaller number of these merchants to service a much larger area much as in bygone days. Javanese astrological belief dictates that an individual’s characteristics and destiny are attributable to the combination of the Pasaran day and the "common" weekday of the Islamic calendar on that person's birthday. Javanese people find great interest in the astrological interpretations of this combination, called the Wetonan cycle; the seven-day-long week cycle is derived from the Islamic calendar, adopted following the spread of Islam throughout the Indonesian archipelago.
The names of the days of the week in Javanese are derived from their Arabic counterparts, namely: These two-week systems occur concurrently. This combination forms the Wetonan cycle; the Wetonan cycle superimposes the five-day Pasaran cycle with the seven-day week cycle. Each Wetonan cycle lasts for 35 days. An example of Wetonan cycle: From the example above, the Weton for Tuesday May 6, 2008 would be read as Selasa Wage; the Wetonan cycle is important for divinatory systems, important celebrations, rites of passage. Commemorations and events are held on days considered to be auspicious. An prominent example, still taught in primary schools, is that the Weton for the Proclamation of Indonesian Independence on 17 August 1945 took place on Jumat Legi. Therefore, Jumat Legi is considered an important night for pilgrimage. There are taboos
An Olympiad is a period of four years associated with the Olympic Games of the Ancient Greeks. Although the Ancient Olympic Games were established during Archaic Greece, it was not until the Hellenistic period, beginning with Ephorus, that the Olympiad was used as a calendar epoch. Converting to the modern BC/AD dating system the first Olympiad began in the summer of 776 BC and lasted until the summer of 772 BC, when the second Olympiad would begin with the commencement of the next games. By extrapolation to the Gregorian calendar, the 3rd year of the 699th Olympiad will begin in mid-summer 2019. A modern Olympiad refers to a four-year period beginning on the opening of the Olympic Games for the summer sports; the first modern Olympiad began in 1896, the second in 1900, so on. The ancient and modern Olympiads would have synchronised had there been a year zero between the Olympiad of 4 BC and the one of 4 AD, but as the Gregorian calendar goes directly from 1 BC to 1 AD, the ancient Olympic cycle now lags the modern cycle by one year.
An ancient Olympiad was a period of four years grouped together, counting inclusively as the ancients did. Each ancient Olympic year overlapped onto two of our modern reckoning of BC or AD years, from midsummer to midsummer. Example: Olympiad 140, year 1 = 220/219 BC. Therefore, the games would have been held in July/August of 220 BC and held the next time in July/August of 216 BC, after four olympic years had been completed; the sophist Hippias was the first writer to publish a list of victors of the Olympic Games, by the time of Eratosthenes, it was agreed that the first Olympic games had happened during the summer of 776 BC. The combination of victor lists and calculations from 776 BC onwards enabled Greek historians to use the Olympiads as a way of reckoning time that did not depend on the time reckonings of one of the city-states; the first to do so was Timaeus of Tauromenium in the third century BC. Since for events of the early history of the games the reckoning was used in retrospect, some of the dates given by historian for events before the 5th century BC are unreliable.
In the 2nd century AD, Phlegon of Tralles summarised the events of each Olympiad in a book called Olympiads, an extract from this has been preserved by the Byzantine writer Photius. Christian chroniclers continued to use this Greek system of dating as a way of synchronising biblical events with Greek and Roman history. In the 3rd century AD, Sextus Julius Africanus compiled a list of Olympic victors up to 217 BC, this list has been preserved in the Chronicle of Eusebius. Early historians sometimes used the names of Olympic victors as a method of dating events to a specific year. For instance, Thucydides says in his account of the year 428 BC: "It was the Olympiad in which the Rhodian Dorieus gained his second victory". Dionysius of Halicarnassus dates the foundation of Rome to the first year of the seventh Olympiad, 752/1 BC. Since Rome was founded on April 21, in the last half of the ancient Olympic year, it would be 751 BC specifically. In Book 1 chapter 75 Dionysius states: "... Romulus, the first ruler of the city, began his reign in the first year of the seventh Olympiad, when Charops at Athens was in the first year of his ten-year term as archon."
Diodorus Siculus dates the Persian invasion of Greece to 480 BC: "Calliades was archon in Athens, the Romans made Spurius Cassius and Proculus Verginius Tricostus consuls, the Eleians celebrated the Seventy-fifth Olympiad, that in which Astylus of Syracuse won the stadion. It was in this year that king Xerxes made his campaign against Greece." Jerome, in his Latin translation of the Chronicle of Eusebius, dates the birth of Jesus Christ to year 3 of Olympiad 194, the 42nd year of the reign of the emperor Augustus, which equates to the year 2 BC. An Olympiad started with the holding of the games, which occurred on the first or second full moon after the summer solstice, in what we call July or August; the games were therefore a new years festival. In 776 BC this occurred on either July 23 or August 21.. Though the games were held without interruption, on more than one occasion they were held by others than the Eleians; the Eleians declared such games Anolympiads, but it is assumed the winners were recorded.
During the 3rd century AD, records of the games are so scanty that historians are not certain whether after 261 they were still held every four years. During the early years of the Olympiad, any physical benefit deriving from a sport was banned; some winners were recorded though, until the last Olympiad of 393AD. In 394, Roman Emperor Theodosius. Though it would have been possible to continue the reckoning by just counting four-year periods, by the middle of the 5th century AD reckoning by Olympiads had become disused; the modern Olympiad is a period of four years, beginning at the opening of the Olympic Summer Games and ending at the opening of the next. The Olympiads are numbered consecutively from the first Games of the Olympiad celebrated in Athens in 1896; the XXXI Olympiad began on August 5, 2016 and will end on July 24, 2020. The Summer Olympics are more referred to as the Games of the Olympiad; the first poster to announce the games using this term was the one for the 1932 Summer Olympics, in Los Angeles, using the phrase: Call to the games of the Xth Olympiad Note, that the official numbering of the Winter Olympics does
The Nanakshahi calendar is a tropical solar calendar, used in Sikhism and is based on the'Barah Maha'. Barah Maha was composed by the Sikh Gurus and translates as the "Twelve Months", it is a poem reflecting the changes in nature which are conveyed in the twelve-month cycle of the Year. The year begins with 1 Chet corresponding to 14 March; the first year of the Nanakshahi Calendar starts in 1469 CE: the year of the birth of Guru Nanak Dev. The Nanakshahi Calendar is named after the founder of Guru Nanak Dev. Sikhs have traditionally recognised luni-solar calendars: the Nanakshahi and Khalsa. Traditionally, both these calendars followed the Bikrami calendar with the Nanakshahi year beginning on Katak Pooranmashi and the Khalsa year commencing with Vaisakhi; the methods for calculating the beginning of the Khalsa era were based on the Bikrami calendar. The year length was the same as the Bikrami solar year. According to Steel, the calendar has twelve lunar months that are determined by the lunar phase, but thirteen months in leap years which occur every 2–3 years in the Bikrami calendar to sync the lunar calendar with its solar counterpart.
Kay abbreviates the Khalsa Era as KE. References to the Nanakshahi Era have been made in historic documents. Banda Singh Bahadur adopted the Nanakshahi calendar in 1710 C. E. after his victory in Sirhind according to which the year 1710 C. E. became Nanakshahi 241. However, Singh states the date of the victory as 14 May 1710 CE. According to Dilagira, Banda "continued adopting the months and the days of the months according to the Bikrami calendar". Banda Singh Bahadur minted new coins called Nanakshahi. Herrli states. Although Banda may have proclaimed this era, it cannot be traced in contemporary documents and does not seem to have been used for dating". According to The Panjab Past and Present, it is Gian Singh who "is the first to use Nanak Shahi Samvats along with those of Bikrami Samvats" in the Twarikh Guru Khalsa. According to Singha, Gian Singh was a Punjabi author born in 1822. Gian Singh wrote the Twarikh Guru Khalsa in 1891; the revised Nanakshahi calendar was designed by Pal Singh Purewal to replace the Bikrami calendar.
The epoch of this calendar is the birth of the first Sikh Guru, Nanak Dev in 1469 and the Nanakshahi year commences on 1 Chet. New Year's Day falls annually on; the start of each month is fixed. According to Kapel, the solar accuracy of the Nanakshahi calendar is linked to the Gregorian civil calendar; this is because the Nanaskhahi calendar uses the tropical year instead of using the sidereal year, used in the Bikrami calendar or the old Nanakshahi and Khalsa calendars. The amended Nanakshahi calendar was adopted in 1998 but implemented in 2003 by the Shiromani Gurdwara Prabhandak Committee to determine the dates for important Sikh events; the calendar was implemented during the SGPC presidency of Sikh scholar Prof. Kirpal Singh Badungar at Takhat Sri Damdama Sahib in the presence of Sikh leadership. Nanakshahi Calendar recognizes the adoption event, of 1999 CE, in the Sikh history when SGPC released the first calendar with permanently fixed dates in the Tropical Calendar. Therefore, the calculations of this calendar do not regress back from 1999 CE into the Bikrami era, fixes for all time in the future.
Features of the Original Nanakshahi calendar: Uses the accurate Tropical year rather than the Sidereal year Called Nanakshahi after Guru Nanak Year 1 is the Year of Guru Nanak's Birth. As an example, April 14, 2019 CE is Nanakshahi 551. Is Based on Gurbani – Month Names are taken from Guru Granth Sahib Contains 5 Months of 31 days followed by 7 Months of 30 days Leap year every 4 Years in which the last month has an extra day Approved by Akal Takht in 2003 In 2010, the Shiromani Gurdwara Prabhandak Committee modified the calendar so that the dates for the start of the months are movable so that they coincide with the Bikrami calendar and changed the dates for various Sikh festivals so they are based upon the lunar phase; this has created controversy with some bodies adopting the original 2003 version called the "Mool Nanakshahi Calendar" and others, the 2010 version. By 2014, the SGPC had scrapped the original Nanakshahi calendar from 2003 and reverted to the Bikrami calendar however it was still published under the name of Nanakshahi.
The Sikh bodies termed it a step taken under pressure from the Shiromani Akali Dal. There is some controversy about the acceptance of the calendar altogether among certain sectors of the Sikh world. SGPC president, Gobind Singh Longowal, on 13 March 2018 urged all Sikhs to follow the current Nanakshahi calendar; the previous SGPC President before Longowal, Prof. Kirpal Singh Badungar, tried to appeal the Akal Takht to celebrate the birthday of Guru Gobind Singh on 23 Poh as per the original Nanakshahi calendar, but the appeal was denied; the PSGPC and a majority of the other gurdwara managements across the world are opposing the modified version of the calendar citing that the SGPC reverted to the Bikrami calendar. They argue that in the Bikrami calendar, dates of many gurpurbs coincide, thereby creating confusion among the Sikh Panth. According to Ahaluwalia, the Nanakshahi calendar goes against the use of lunar Bikrami dates by the Gurus themselves and is contradictory, it begins with the year of birth of
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