1440s in architecture
1440s Great Tower of Tattershall Castle, England, is largely completed. Wilcote Chapel of St Mary's Church, North Leigh, England, is built. 1440 Guildhall, London, is completed. Sidi Yahya Mosque in Timbuktu is completed. St. Nicolai, Lüneburg, is completed. 1441 The nave of the Church of the Holy Spirit, Germany, is completed. Construction of Herstmonceux Castle in England is begun. 1442 The Porta della Carta, built by Giovanni and his son Bartolomeo Bon, completes the Doge's Palace, Venice. Chapel of All Souls College, consecrated. 1443 – The Castle of Zafra is completed. 1445 Church of San Pablo, Valladolid is begun. Palazzo Medici in Florence is begun by Michelozzo. 1446 July 25 – The foundation stone of King's College Chapel, England is laid by King Henry VI of England. Precious Belt Bridge in China reconstructed. Approximate date Jama Masjid of Herat in Afghanistan is completed Construction of Palazzo Rucellai in Florence designed by Leon Battista Alberti and executed, at least in part, by Bernardo Rossellino, is begun.
Construction of Ockwells Manor in Berkshire, England, is begun. 1446–1450 – Reconstruction of choir of Mont Saint Michel Abbey in Normandy is begun. C. 1447 – Llotja dels Mercaders in Palma, designed by Guillem Sagrera, completed. C. 1440 – Reginald Bray born in Worcester, England c. 1443 – Giuliano da Sangallo born in Florence c. 1444 – Donato Bramante born in Monte Asdrualdo, Italy 1446: April 16 – Filippo Brunelleschi dies in Florence
The 16th century begins with the Julian year 1501 and ends with either the Julian or the Gregorian year 1600. The 16th century is regarded by historians as the century. During the 16th century and Portugal explored the world's seas and opened worldwide oceanic trade routes. Large parts of the New World became Spanish and Portuguese colonies, while the Portuguese became the masters of Asia's and Africa's Indian Ocean trade, the Spanish opened trade across the Pacific Ocean, linking the Americas with Asia; this era of colonialism established mercantilism as the leading school of economic thought, where the economic system was viewed as a zero-sum game in which any gain by one party required a loss by another. The mercantilist doctrine encouraged the many intra-European wars of the period and arguably fueled European expansion and imperialism throughout the world until the 19th century or early 20th century. In Europe, the Protestant Reformation gave a major blow to the authority of the papacy and the Roman Catholic Church.
European politics became dominated by religious conflicts, with the groundwork for the epochal Thirty Years' War being laid towards the end of the century. In Italy, Luca Pacioli published the first work on accounting and Galileo Galilei made the first thermometer. In England, the Italian Alberico Gentili wrote the first book on public international law and divided secularism from canon law and Roman Catholic theology. In the Middle East, the Ottoman Empire continued to expand, with the Sultan taking the title of Caliph, while dealing with a resurgent Persia. Iran and Iraq were caught by major popularity of the Shiite sect of Islam under the rule of the Safavid dynasty of warrior-mystics, providing grounds for a Persia independent of the majority-Sunni Muslim world. China evacuated the coastal areas, because of Japanese piracy. Japan was suffering a severe civil war at the time, known as the Sengoku period. Elsewhere in Asia, Mughal Emperor Akbar extended the power of the Mughal Empire to cover most of the southern lands of the continent.
His rule influenced arts and culture in the region. Copernicus proposed the heliocentric universe, met with strong resistance, Tycho Brahe refuted the theory of celestial spheres through observational measurement of the 1572 appearance of a Milky Way supernova; these events directly challenged the long-held notion of an immutable universe supported by Ptolemy and Aristotle, led to major revolutions in astronomy and science. Polybius' "The Histories" translated into Italian, English and French. Mississippian culture disappears. Medallion rug, variant Star Ushak style, Anatolia, is made, it is now kept at The Saint Louis Art Museum. 1500: Charles V, Holy Roman Emperor and King of Spain was born. 1500: Guru Nanak the beginning and spreading of the 5th largest religion in the world Sikhism. 1500: Spanish navigator Vicente Yáñez Pinzón encounters Brazil but is prevented from claiming it by the Treaty of Tordesillas. 1500: Portuguese navigator Pedro Álvares Cabral claims Brazil for Portugal. 1500: The Ottoman fleet of Kemal Reis defeats the Venetians at the Second Battle of Lepanto.
1501: Michelangelo returns to his native Florence to begin work on the statue David. 1501: Safavid dynasty reunified Iran and ruled over it until 1736. Safavids adopt a Shia branch of Islam. 1502: First reported African slaves in The New World 1503: Foundation of the Sultanate of Sennar by Amara Dunqas, in what is modern Sudan 1503: Spain defeats France at the Battle of Cerignola. Considered to be the first battle in history won by gunpowder small arms. 1503: Leonardo da Vinci begins painting the Mona Lisa and completes it three years later. 1503: Nostradamus was born on either December 14, or December 21. 1504: A period of drought, with famine in all of Spain. 1504: Death of Isabella I of Castile, Joanna of Castille became the Queen. 1505: Zhengde Emperor ascended the throne of Ming Dynasty. 1505: Martin Luther enters St. Augustine's Monastery at Erfurt, Germany, on 17 July and begins his journey to instigating the Reformation. 1505: King Sultan Trenggono built the first Muslim kingdom in Java, called Demak, in Indonesia's of a homelessness of a.
Many other small kingdoms were established in other islands to fight against Portuguese. Each kingdom introduced local language as a way of unity. 1506: Leonardo da Vinci completes the Mona Lisa. 1506: King Afonso I of Kongo wins the battle of Mbanza Kongo, resulting in Catholicism becoming Kongo's state religion. 1506: At least two thousand converted Jews are massacred in a Lisbon riot, Portugal. 1506: Christopher Columbus dies in Valladolid, Spain. 1506: Poland is invaded by Tatars from the Crimean Khanate. 1507: The first recorded epidemic of smallpox in the New World on the island of Hispaniola. It devastates the native Taíno population. 1507: Afonso de Albuquerque conquered Hormuz and Muscat, among other bases in the Persian Gulf, taking control of the region at the entrance of the Gulf. 1508–1512: Michelangelo paints the Sistine Chapel ceiling. 1509: The Battle of Diu marks the beginning of Portuguese dominance of the Spice trade and the Indian Ocean. 1509: The Portuguese king sends Diogo Lopes de Sequeira to find Malacca, the eastern terminus of Asian trade.
After receiving Sequeira, Sultan Mahmud Syah captures and/or kills several of his men and attempts an assault on the four Portuguese ships, which escape. The Javanese fleet is destroyed in Malacca.. 1509–10: The'great plague' in various parts of Tudor England. 1511: Afonso de Albuquerque of Portugal conquers Malacca, the capital of the Sultanate of Malacca in present-day Malaysia. 1512: Copernicus writes Commentar
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
Vikram Samvat. It uses solar sidereal years; the Vikram Samvat is notable because many medieval era inscriptions use it. It is said to be named after the legendary king Vikramaditya, but the term "Vikrama Samvat" does not appear in the historical records before the 9th century, rather the same calendaring system is found by other names such as Krita and Malava. In the colonial era scholarship, the era was believed to be based on the commemoration of King Vikramaditya expelling the Sakas from Ujjain; however epigraphical evidence and scholarship suggest that this theory has no historical basis and likely was an error. Starting in the 9th century and thereafter, epigraphical artwork uses Vikrama-Samvat, suggesting that sometime around the 9th-century, the Hindu calendar era, in use became popular as Vikram Samvat, while Buddhist and Jain epigraphy continued to use an era based on the Buddha or the Mahavira. According to popular tradition, the legendary king Vikramaditya of Ujjain established the Vikrama Samvat era after defeating the Śakas.
Kalakacharya Kathanaka by the Jain sage Mahesarasuri gives the following account: Gandharvasena, the then-powerful king of Ujjain, abducted a nun called Sarasvati, the sister of the monk. The enraged monk sought the help of the Śaka ruler King Sahi in Sistan. Despite heavy odds but aided by miracles, the Śaka king defeated Gandharvasena and made him a captive. Sarasvati was repatriated; the defeated king retired to the forest. His son, being brought up in the forest, had to rule from Pratishthana. On, Vikramaditya invaded Ujjain and drove away from the Śakas. To commemorate this event, he started a new era called the "Vikrama era"; the Ujjain calendar started around 58–56 BCE, the subsequent Shaka era calendar was started in 78 CE at Pratishthana. The association of the era beginning in 57 BCE with Vikramaditya is not found in any source before the 9th century CE; the earlier sources call this era by various names, including Kṛṭa, the era of the Malava tribe, or Samvat. The earliest known inscription that calls the era "Vikrama" is from 842 CE.
This inscription of Chauhana ruler Chandamahasena was found at Dholpur, is dated Vikrama Samvat 898, Vaishakha Shukla 2, Chanda. The earliest known inscription that associates this era with a king called Vikramaditya is dated 971 CE; the earliest literary work that connects the era to Vikramaditya is Subhashita-Ratna-Sandoha by the Jain author Amitagati. For this reason, multiple authors believe that the Vikram Samvat was not started by Vikramaditya, who might be a purely legendary king or the title adopted by a king who renamed the era after himself. V. A. Smith and D. R. Bhandarkar believed that Chandragupta II adopted the title Vikramaditya, changed the name of the era to "Vikrama Samvat". According to Rudolf Hoernlé, the king responsible for this change was Yashodharman: Hoernlé believed that he conquered Kashmir, is the same person as the "Harsha Vikramaditya" mentioned in Kalhana's Rajatarangini. Earlier, some scholars believed that the Vikrama Samavat corresponded to the Azes era of the Indo-Scythian king King Azes.
However, this was disputed by Robert Bracey following the discovery of an inscription of Vijayamitra, dated in two eras. The theory seems to be now discredited by Falk and Bennett, who place the inception of the Azes era in 47–46 BCE; the traditional New Year of Vikram Samvat is one of the many festivals of Nepal, marked by parties, family gatherings, the exchange of good wishes, participation in rituals to ensure good fortune in the coming year. It occurs in mid-April each year, coincides with the traditional new year in Assam, Burma, Kerala, Manipur, Punjab, Sri Lanka, Tamil Nadu and Thailand. In addition to Nepal, the Vikram Samvat calendar is recognized in North and East India, in Gujarat among Hindus. Hindu religious festivals are based on a Luni-Solar calendar, not Solar calendar, based on Vikram Samvat. In North India, the new year in Vikram Samvat starts from the first day of Chaitra Skukla paksha. In Buddhist communities, the month of Baishakh is associated with Buddha's Birthday, it commemorates the birth and passing of Gautama Buddha on the first full moon day in May, except in a leap year when the festival is held in June.
Although this festival is not held on the same day as Pahela Baishakh, the holidays fall in the same month of the Bengali and Theravada Buddhist calendars, are related through the spread of Hinduism and Buddhism in the Indian subcontinent. In Gujarat, the day after Diwali is celebrated as the first day of the Vikram Samvat calendar, the first day of the month Kartik; the Vikrami era is an ancient calendar and has been used by Hindus and Sikhs. It is one of the several regional Hindu calendars that have been in use on the Indian subcontinent, it is based on twelve synodical lunar months and 365 solar days; the lunar new year starts on the new moon in the month of Chaitra. This day, known as Chaitra Sukhladi, is a restricted holiday in India; the Vikrami Samvat has been in use in the Indian subcontinent since ancient times, remains in use by the Hindus in north, w
As a means of recording the passage of time, the 14th century was a century lasting from January 1, 1301, to December 31, 1400. During this period and natural disasters ravaged both Europe and the four khanates of the Mongol Empire; the Mongol court was driven out of China and retreated to Mongolia, the Ilkhanate collapsed in Persia, the Chaghatayid dissolved and broke into two parts, the Golden Horde lost its position as a great power in Eastern Europe. In Europe, the Black Death claimed between 75 and 200 million lives – wiping out over 60 percent of European society – while England and France fought in the protracted Hundred Years' War after the death of Charles IV, King of France led to a claim to the French throne by Edward III, King of England; this period is considered the height of chivalry and marks the beginning of strong separate identities for both England and France. The transition from the Medieval Warm Period to the Little Ice Age. Beginning of the Ottoman Empire, early expansion into the Balkans.
Early 14th century: Attributed to Kao Ninga Monk Sewing is made. Kamakura period, it is now kept at The Cleveland Museum of Art. An account of Buddha's life, translated earlier into Greek by Saint John of Damascus and circulated to Christians as the story of Barlaam and Josaphat, became so popular that the two were venerated as saints. Singapore emerges for the first time as a fortified trading centre of some importance. Islam reaches Terengganu, on the Malay Peninsula; the Hausa found several city-states in the south of modern Niger. The poet Petrarch coins the term Dark Ages to describe the preceding 900 years in Europe, beginning with the fall of the Western Roman Empire in 476 through to the renewal embodied in the Renaissance. Iwan vault, Jamé Mosque of Isfahan, Persia, is built. Work begins on the Great Enclosure at Great Zimbabwe, built of dressed stone; the city's population is now between 10,000 and 40,000. 1309 — King Jayanegara succeeds Kertarajasa Jayawardhana as ruler of Majapahit. 1309-1377 — The Avignon papacy transfers the seat of the Popes from Italy to France The Great Famine of 1315-1317 kills millions of people in Europe.
1318-1330 — An Italian Franciscan friar, Mattiussi visited Sumatra and Banjarmasin in Borneo. In his record he described the kingdom of Majapahit. 1320 — Władysław I the Elbow-high is crowned King of Poland which leads to its unification 1323 — Malietoafaiga ordered cannibalism to be abolished in Tutuila, now known as American Samoa. 1325 — Forced out of previous locations, the Mexica found the city of Tenochtitlan 1328 — Tribhuwana Wijayatunggadewi succeeds Jayanegara as ruler of Majapahit. Beginning of the Renaissance in Italy 1335 — The death of the Ilkhan Abu Said, causes the disintegration of the Mongol rule in Persia. 1336 — The Vijayanagara Empire is founded in South India by Harihara 1337 — The Hundred Years' War begins when Edward III of England lays claim to the French throne. 1345–1346 — The French recruit troops and ships in Genoa and Nice. 1346 — English forces led by Edward III defeat a French army led by Philip VI in The Battle of Crécy, a major point in the Hundred Years' War which marks the rise of the longbow as a dominant weapon in Western Europe.
1347–1351 — The Black Death kills around a third of the population of Europe. 1347 — Adityawarman moved the capital of Dharmasraya and established the kingdom of Malayupura in Pagarruyung, West Sumatra. 1350 — Hayam Wuruk, styled Sri Rajasanagara, succeeds Tribhuwana Wijayatunggadewi as ruler of Majapahit. Under its military commander Gajah Mada, Majapahit stretches over much of modern-day Indonesia. 1356 — The Imperial Diet of the Holy Roman Empire headed by Emperor Charles IV issues the Golden Bull of 1356, establishing various constitutional aspects of the Empire, the most significant being the electoral college to elect future emperors. 1356 — The Diet of the Hansa is held in Lübeck, formalising what up until had only been a loose alliance of trading cities in northern Europe and founding the Hanseatic League. 1357 — Scotland retains its independence with the signing of the Treaty of Berwick, thus ending the Wars of Scottish Independence. 1357 — In the Battle of Bubat, the Sundanese royal family is massacred by the Majapahit army by the order of Gajah Mada.
1363 — The Battle of Lake Poyang, a naval conflict between Chinese rebel groups led by Chen Youliang and Zhu Yuanzhang, takes place from August to October, constituting one of the largest naval battles in history. 1365 — The Old Javanese text Nagarakertagama is written. 1366 — Tepanec Tlatoani Acolnahuácatl accepts Acamapichtli as the first tlatoani of Tenochtitlan for the Mexica Empire. 1368 — The end of the Mongol Yuan Dynasty in China and the beginning of the Ming Dynasty. 1377 — Majapahit sends a punitive expedition against Palembang in Sumatra. Palembang's prince, Parameswara flees finding his way to Malacca and establishing it as a major international port. 1378 — The Great Schism of the West begins leading to 3 simultaneous popes. 1378-1382 — Ciompi Revolt occurs in Florence 1381 — John Wycliffe is dismissed from the University of Oxford for criticism of the Roman Catholic Church thus, the Lollardy movement rises in England. 1381 — Peasants' Revolt in England. 1385 — Battle of Aljubarrota between Portugal and Castile.
Portugal maintains independence. 1385 — Union of Krewo between Poland and Lithuania. 1389 — Battle of Kosovo between Serbs and Ottoman Turks, Prince Lazar, sultan Murat I and Miloš Obilić were killed. 1389 — Wikramawardhana succeeds Sri Rajasanagara as ruler of Majapahit. 1392 — Taejo
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