4th century BC
The 4th century BC started the first day of 400 BC and ended the last day of 301 BC. It is considered part of epoch, or historical period; this century marked the height of Classical Greek civilization in all of its aspects. By the year 400 Greek philosophy, art and architecture had spread far and wide, with the numerous independent Greek colonies that had sprung up throughout the lands of the eastern Mediterranean. Arguably the most important series of political events in this period were the conquests of Alexander, bringing about the collapse of the once formidable Persian Empire and spreading Greek culture far into the east. Alexander dreamed of an east/west union, but when his short life ended in 323 BC, his vast empire was plunged into civil war as his generals each carved out their own separate kingdoms, thus began the Hellenistic age, a period characterized by a more absolute approach to rule, with Greek kings taking on royal trappings and setting up hereditary successions. While a degree of democracy still existed in some of the remaining independent Greek cities, many scholars see this age as marking the end of classical Greece.
In India, the Mauryan Empire was founded in 322 BC by Chandragupta Maurya who expanded his power westwards across central and western India, taking advantage of the disruptions of local powers in the wake of the withdrawal westward by the armies of Alexander. China in the 4th century BC entered an era of constant warfare known as the Warring States period; the period saw the rapid rise of large states over smaller ones thanks to technological advancement. Though the period has been characterized by historians as being excessively violent compared to the Spring and Autumn period, it was punctured by several cultural and social growths through the expansion of several different sects of Confucianism and Taoism, the formulation of Legalist thought. Oldest Brāhmī script dates from this period. Brāhmī is the ancestor of Brahmic scripts, used in much of Southeast Asia. Romans build their first aqueduct. Chinese use the handheld trigger crossbow for the first time; the first crossbow, the gastraphetes, is invented at Syracuse.
Burnt brick'or fired bricks' were first used in Medeterranean Civilizations. Donkey-powered mills or ` Pompeiian Mills' were first used in Italy. In Greece, Aristotle proposes the division of the known sciences. Torque with lion's-head terminals, from Susa was made, it is now in Paris. Daric, a coin first minted under Darius I of Persia is made, it is now kept in Ashmolean Museum, Oxford. Second half of the 4th century BC – Tomb II, so called Tomb of Philip II of Macedon, Macedonia is made. Starting in the year 309 BC, the Chinese historian Sima Qian wrote that the Qin-employed engineer Bi Ling of the newly conquered State of Shu in Sichuan had the shoulder of a mountain cut through, making the'Separated Hill' that abated the Mo River, excavated two canals in the plain of Chengdu; the significance of this was phenomenal, as it allowed the new Guardian irrigation system to populate an area of some 40 by 50 miles with over five million people, still in use today. The Chinese astronomer Gan De divides the celestial sphere into 365¼ degrees, the tropical year into 365¼ days at a time when most astronomers used the Babylon division of the celestial sphere as 360 degrees.
First written in Sanskrit. Agnodice, female Athenian physician and midwife Alexander the Great, king of Macedon Antigonus I Monophthalmus, Macedonian diadoch Antipater, Macedonian statesman Atropates, Persian nobleman Bessus, Persian satrap of Bactria Cassander, King of Macedon Chandragupta Maurya, Founder of the "Mauryan Dynasty" Craterus, Macedonian diadoch Darius III, king of the Achaemenid Empire Demetrius Poliocretes, King of Macedon Demosthenes, Athenian statesman and orator Dhana Nanda, last emperor of the Nanda dynasty Duke Xiao of Qin, ruler of Qin Epaminondas, Theban statesman Hephaestion, Macedonian general King Wuling of Zhao, ruler of Zhao Lysimachus, Macedonian diadoh and king of Thrace Mahapadma Nanda, founding emperor of the Nanda dynasty Manius Curius Dentatus, Roman statesman Nakhthorheb, last native Pharaoh of Egypt Pang Juan, Chinese general Parmenion, Macedonian general Pelopidas, Theban statesman Perdiccas, Macedonian diadoh Philip II, King of Macedon Ptolemy I Soter, Macedonian diadoh and king of Egypt Porus, King of the Pauravas, in the Indian Subcontinent Seleucus I Nicator, Macedonian diadoh and founder of the Seleucid Empire Shang Yang, Chinese statesman Su Qin, Chinese politician and strategist Tian Ji, Chinese general Zhang Yi, Chinese strategist Apelles, Greek painter Cephisodotus the Elder, Greek sculptor Leochares, Greek sculptor Lysippos, Greek sculptor Praxiteles, Greek sculptor Scopas, Greek sculptor and architect Demetrius of Phalerum, Greek rhetorician Isocrates, Greek rhetorician and writer Menander, Greek playwright Onesicritus, Greek historical writer Qu Yuan, Chinese poet Simonides of Ceos, Greek lyric poet Xenophon, Greek historian and writer Anaximenes of Lampsacus, Greek rhetorician and historian.
Antisthenes, Greek philosopher Archytas, Greek philosopher Aristippus, Greek philosopher Aristotle, Greek philosopher Callisthenes, Greek historian Chanakya, Indian economist and political advisor Crates of Thebes, Greek philosopher Diogenes of Sinope, Greek philosopher Epicurus, Greek philosopher Mencius, Chinese philosopher Panini, Indian philosopher and writer Plato, Greek philosopher Pyrrho, Greek philosopher Socrates, Greek Philo
1st millennium BC
The 1st millennium BC is the period of time between from the year 1000 BC to 1 BC. It encompasses the Iron Age in the Old World and sees the transition from the Ancient Near East to classical antiquity. World population doubled over the course of the millennium, from about 100 million to about 200–250 million; the Neo-Assyrian Empire dominates the Near East in the early centuries of the millennium, supplanted by the Achaemenid Empire in the 6th century. Ancient Egypt is in decline, falls to the Achaemenids in 525 BC. In Greece, Classical Antiquity begins with the colonization of Magna Graecia and peaks with the conquest of the Achaemenids and the subsequent flourishing of Hellenistic civilization; the Roman Republic supplants the Etruscans and the Carthaginians. The close of the millennium sees the rise of the Roman Empire; the early Celts dominate Central Europe. In East Africa, the Nubian Empire and Aksum arise. In South Asia, the Vedic civilization blends into the Maurya Empire; the Scythians dominate Central Asia.
In China, the Spring and Autumn period sees the rise of Confucianism. Towards the close of the millennium, the Han Dynasty extends Chinese power towards Central Asia, where it borders on Indo-Greek and Iranian states. Japan is in the Yayoi period; the Maya civilization rises in Mesoamerica. The first millennium BC is the formative period of the classical world religions, with the development of early Judaism Zoroastrianism in the Near East, Vedic religion and Vedanta and Buddhism in India. Early literature develops in Greek, Hebrew, Sanskrit and Chinese; the term Axial Age, coined by Karl Jaspers, is intended to express the crucial importance of the period of c. the 8th to 2nd centuries BC in world history. World population more than doubled over the course of the millennium, from about an estimated 50–100 million to an estimated 170–300 million. Close to 90% of world population at the end of the first millennium BC lived in the Iron Age civilizations of the Old World; the population of the Americas was below 20 million, concentrated in Mesoamerica.
The population of Oceania was less than one million people. 10th century BC Near East: Neo-Assyrian Empire Near East: Shoshenq I invades Canaan Aegean: Helladic period ends 9th century BC Egypt: 872 BC: Nile floods the Temple of Luxor Egypt: 836 BC: Civil war in Egypt North Africa: 814 BC: Carthage founded China: 841 BCndash. Greece: Archaic Greece, Greek alphabet Greece: Homer 776 BC: Greece: First Olympiad 753 BC: Europe: foundation of Rome 7th century BC 671 BC: Assyrian conquest of Egypt Near East: 631 BC: Death of Ashurbanipal, decline of the Assyrian Empire 6th century BC Egypt: 592 BC: Psamtik II sacks Napata Sudan: Aspelta moves the Kushite capital to Meroe Near East: 539 BC: Achaemenid conquest of Babylon under Cyrus the Great South Asia: Śramaṇa movement and "second urbanisation" South Asia: Early Buddhism Europe: 509 BC: Roman Republic 5th century BC China: 479 BC: death of Confucius China: 476 BC: Warring States period China: 486 BC: Grand Canal construction begins Near East: Second Temple Judaism, redaction of the Hebrew Bible Greece: beginning of the classical period.
Greece: Greco-Persian Wars Greece: 440 BC: Herodotus' Histories Greece: 431 BC: Peloponnesian War Oceania: Austronesian expansion reaches Western Polynesia 4th century BC Greece: 395 BC: Corinthian War Egypt: 343 BC: Achaemenid conquest Greece/Asia/Egypt: 330s BC: conquests of Alexander the Great, end of the Achaemenid Empire, Macedonian Empire, beginning of the Hellenistic period South Asia: Mauryan Empire 3rd century BC China: Qin Unified China China: 206 BC: Han Dynasty South Asia: 261 BC: Kalinga war Rome: Roman expansion in Italy Rome/Carthage: Punic Wars 264 BC: First Punic War 218 BC Second Punic War 2nd century BC Rome/Carthage: 149 BC Third Punic War, Roman province of Africa Rome/Greece: 146 BC Battle of Corinth, beginning of the Roman era South Asia: 185 BC: Fall of the Maurya Empire China: Confucianism became the state ideology of China 1st century BC China: 91 BC: Records of the Grand Historian finished Rome/Europe: 58-50 BC Gallic Wars Rome: 32/30 BC: Final War of the Roman Republic Rome/Egypt: 31 BC: Roman conquest of Egypt Rome/Europe/West Asia/Africa: 27 BC: Roman Empire Some of the central figures of the Axial Age are legendary or semi-legendary, with no contemporary written records available RulersChina: Dynasties in Chinese history, List of Chinese monarchs Egypt: Third Intermediate Period of Egypt Carthage: List of monarchs of Carthage Assyrian Empire: List of Assyrian kings Babylonia: Neo-Babylonian_dynasty Canaan / Biblical Levant: Kings of Israel and Judah Achaemenid Persia: List of monarchs of Persia Kingdom of Kush: List of monarchs of Kush Classical Greece: Monarchs: List of kings of Sparta, Thirty Tyrants Athenian democracy: Pericles Macedon: List of ancient Macedonians, Argead dynasty Hellenistic period: Ptolemaic Dynasty, Antigonid dynasty, Hasmonean dynasty Rome: kings of Rome, List of Roman consuls Parthian Empire: List of Parthian kings India: List of Indian monarchsReligion, p
The Horse is the seventh of the 12-year cycle of animals which appear in the Chinese zodiac related to the Chinese calendar. There is a long tradition of the Horse in Chinese mythology. Certain characteristics of the Horse nature are supposed to be typical of or to be associated with either a year of the Horse and its events, or in regard to the personality of someone born in such a year. Horse aspects can enter by other chronomantic factors or measures, such as hourly. People born within these date ranges can be said to have been born in the "Year of the Horse", while bearing the following elemental sign: Horse Chinese astrology Chinese New Year Burmese zodiac Horse worship Hale, Jill; the Practical Encyclopedia of Feng Shui. New York: Barnes and Noble Books. ISBN 0-7607-3741-X
Balinese saka calendar
The Balinese saka calendar is one of two calendars used on the Indonesian island of Bali. Unlike the 210-day pawukon calendar, it is based on the phases of the Moon, is the same length as the Gregorian year. Based on a lunar calendar, the saka year comprises sasih, of 30 days each. However, because the lunar cycle is shorter than 30 days, the lunar year has a length of 354 or 355 days, the calendar is adjusted to prevent it losing synchronization with the lunar or solar cycles; the months are adjusted by allocating two lunar days to one solar day every 9 weeks. This day is called ngunalatri, Sanskrit for "minus one night". To stop the Saka from lagging behind the Gregorian calendar – as happens with the Islamic calendar, an extra month, known as an intercalary month, is added after the 11th month, or after the 12th month; the length of these months is calculated according to the normal 63-day cycle. An intercalary month is added whenever necessary to prevent the final day of the 7th month, known as Tilem Kapitu, from falling in the Gregorian month of December.
The names the twelve months are taken from a mixture of Old Balinese and Sanskrit words for 1 to 12, are as follows: Kasa Karo Katiga Kapat Kalima Kanem Kapitu Kawalu Kasanga Kadasa Jyestha SadhaEach month begins the day after a new moon and has 15 days of waxing moon until the full moon 15 days of waning, ending on the new moon. Both sets of days are numbered 1 to 15; the first day of the year is the day after the first new moon in March. Note, that Nyepi falls on the first day of Kadasa, that the years of the Saka era are counted from that date; the calendar is 78 years behind the Gregorian calendar, is calculated from the beginning of the Saka Era in India. It is used alongside the 210-day Balinese pawukon calendar, Balinese festivals can be calculated according to either year; the Indian saka calendar was used for royal decrees as early as the ninth century CE. The same calendar was used in Java until Sultan Agung replaced it with the Javanese calendar in 1633; the Balinese Hindu festival of Nyepi, the day of silence, marks the start of the Saka year.
Tilem Kepitu, the last day of the 7th month, is known as Siva Ratri, is a night dedicated to the god Shiva. Devotees stay up all meditate. There are another 24 ceremonial days in the Saka year celebrated at Purnama. Eiseman, Fred B. Jr, Bali: Sekalia and Niskala Volume I: Essays on Religion and Art pp 182–185, Periplus Editions, 1989 ISBN 0-945971-03-6 Haer, Debbie Guthrie. ISBN 981 3018 496 Hobart, Angela. ISBN 0 631 17687 X Ricklefs, M. C.
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
The Ethiopian calendar or Eritrean calendar is the principal calendar used in Ethiopia and serves as the liturgical year for Christians in Eritrea and Ethiopia belonging to the Eritrean Orthodox Tewahedo Church, Ethiopian Orthodox Tewahedo Church, Eastern Catholic Churches, the Coptic Orthodox Church of Alexandria, Ethiopian-Eritrean Evangelicalism. It is a solar calendar which in turn derives from the Egyptian calendar, but like the Julian calendar, it adds a leap day every four years without exception, begins the year on August 29 or August 30 in the Julian calendar. A gap of 7–8 years between the Ethiopian and Gregorian calendars results from an alternative calculation in determining the date of the Annunciation. Like the Coptic calendar, the Ethiopic calendar has 12 months of 30 days plus 5 or 6 epagomenal days, which comprise a thirteenth month; the Ethiopian months begin on the same days as those of the Coptic calendar, but their names are in Ge'ez. A 6th epagomenal day is added every 4 years, without exception, on August 29 of the Julian calendar, 6 months before the corresponding Julian leap day.
Thus the first day of the Ethiopian year, 1 Mäskäräm, for years between 1900 and 2099, is September 11. However, it falls on September 12 in years before the Gregorian leap year. Enkutatash is the word for the Ethiopian New Year in Amharic, the official language of Ethiopia, while it is called Ri'se Awde Amet in Ge'ez, the term preferred by the Ethiopian & Eritrean Orthodox Tewahedo Churchs, it occurs on September 11th in the Gregorian Calendar. The Ethiopian Calendar Year 1998 Amätä Məhrät began on the Gregorian Calendar Year on September 11th, 2005. However, the Ethiopian Years 1992 and 1996 began on the Gregorian Dates of'September 12th 1999' and'2003' respectively; this date correspondence applies for the Gregorian years 1900 to 2099. The Ethiopian leap year is every four without exception, while Gregorian centurial years are only leap years when divisible by 400; as the Gregorian year 2000 is a leap year, the current correspondence lasts two centuries instead. The start of the Ethiopian year falls on August 30th.
This date corresponds to the Old-Style Julian Calendar. This deviation between the Julian and the Gregorian Calendar will increase with the passing of the time. You can observe the real start date in the future centuries in a Gregorian to Ethiopian Date Converter. To indicate the year and followers of the Eritrean churches today use the Incarnation Era, which dates from the Annunciation or Incarnation of Jesus on March 25, AD 9, as calculated by Annianus of Alexandria c. 400. Meanwhile, Europeans adopted the calculations made by Dionysius Exiguus in AD 525 instead, which placed the Annunciation 8 years earlier than had Annianus; this causes the Ethiopian year number to be 8 years less than the Gregorian year number from January 1 until September 10 or 11 7 years less for the remainder of the Gregorian year. In the past, a number of other eras for numbering years were widely used in Ethiopia and the Kingdom of Aksum; the most important era – once used by the Eastern Christianity, still used by the Coptic Orthodox Church of Alexandria – was the Era of Martyrs known as the Diocletian Era, or the era of Diocletian and the Martyrs, whose first year began on August 29, 284.
Respective to the Gregorian and Julian New Year's Days, 31⁄2 to 4 months the difference between the Era of Martyrs and the Anni Domini is 285 years. This is because in AD 525, Dionysius Exiguus decided to add 15 Metonic cycles to the existing 13 Metonic cycles of the Diocletian Era to obtain an entire 532 year medieval Easter cycle, whose first cycle ended with the year Era of Martyrs 247 equal to year DXXXI, it is because 532 is the product of the Metonic cycle of 19 years and the solar cycle of 28 years. Around AD 400, an Alexandrine monk called Panodoros fixed the Alexandrian Era, the date of creation, on 29 August 5493 BC. After the 6th century AD, the era was used by Ethiopian chronologists; the twelfth 532 year-cycle of this era began on 29 August AD 360, so 4×19 years after the Era of Martyrs. Bishop Anianos preferred the Annunciation style as 25 March, thus he shifted the Panodoros era by about six months, to begin on 25 March 5492 BC. In the Ethiopian calendar this was equivalent to 15 Magabit 5501 B.
C.. The Anno Mundi era remained in usage until the late 19th century; the 4 year leap-year cycle is associated with the four Evangelists: the first year after an Ethiopian leap year is named the John-year, followed by the Matthew-year, the Mark-year. The year with the 6th epagomenal day is traditionally designated as the Luke-year. There are no exceptions to the 4 year leap-year cycle, like the Julian calendar but unlike the Gregorian calendar; these dates are valid only from March 1900 to February 2100. This is because 1900 and 2100 are not leap years in the Gregorian calendar, while they are still leap year
The Hebrew or Jewish calendar is a lunisolar calendar used today predominantly for Jewish religious observances. It determines the dates for Jewish holidays and the appropriate public reading of Torah portions and daily Psalm readings, among many ceremonial uses. In Israel, it is used for religious purposes, provides a time frame for agriculture and is an official calendar for civil purposes, although the latter usage has been declining in favor of the Gregorian calendar; the present Hebrew calendar is the product including a Babylonian influence. Until the Tannaitic period, the calendar employed a new crescent moon, with an additional month added every two or three years to correct for the difference between twelve lunar months and the solar year; the year in which it was added was based on observation of natural agriculture-related events in ancient Israel. Through the Amoraic period and into the Geonic period, this system was displaced by the mathematical rules used today; the principles and rules were codified by Maimonides in the Mishneh Torah in the 12th century.
Maimonides' work replaced counting "years since the destruction of the Temple" with the modern creation-era Anno Mundi. The Hebrew lunar year is about eleven days shorter than the solar year and uses the 19-year Metonic cycle to bring it into line with the solar year, with the addition of an intercalary month every two or three years, for a total of seven times per 19 years. With this intercalation, the average Hebrew calendar year is longer by about 6 minutes and 40 seconds than the current mean tropical year, so that every 217 years the Hebrew calendar will fall a day behind the current mean tropical year; the era used. As with Anno Domini, the words or abbreviation for Anno Mundi for the era should properly precede the date rather than follow it. AM 5779 began at sunset on 9 September 2018 and will end at sunset on 29 September 2019; the Jewish day is of no fixed length. The Jewish day is modeled on the reference to "...there was evening and there was morning..." in the creation account in the first chapter of Genesis.
Based on the classic rabbinic interpretation of this text, a day in the rabbinic Hebrew calendar runs from sunset to the next sunset. Halachically, a day ends and a new one starts when three stars are visible in the sky; the time between true sunset and the time when the three stars are visible is known as'bein hashmashot', there are differences of opinion as to which day it falls into for some uses. This may be relevant, for example, in determining the date of birth of a child born during that gap. There is no clock in the Jewish scheme. Though the civil clock, including the one in use in Israel, incorporates local adoptions of various conventions such as time zones, standard times and daylight saving, these have no place in the Jewish scheme; the civil clock is used only as a reference point – in expressions such as: "Shabbat starts at...". The steady progression of sunset around the world and seasonal changes results in gradual civil time changes from one day to the next based on observable astronomical phenomena and not on man-made laws and conventions.
In Judaism, an hour is defined as 1/12 of the time from sunrise to sunset, so, during the winter, an hour can be much less than 60 minutes, during the summer, it can be much more than 60 minutes. This proportional hour is known as a sha'ah z'manit. A Jewish hour is divided into parts. A part is 1/18 minute; the ultimate ancestor of the helek was a small Babylonian time period called a barleycorn, itself equal to 1/72 of a Babylonian time degree. These measures are not used for everyday purposes. Instead of the international date line convention, there are varying opinions as to where the day changes. One opinion uses the antimeridian of Jerusalem. Other opinions exist as well; the weekdays proceed to Saturday, Shabbat. Since some calculations use division, a remainder of 0 signifies Saturday. While calculations of days and years are based on fixed hours equal to 1/24 of a day, the beginning of each halachic day is based on the local time of sunset; the end of the Shabbat and other Jewish holidays is based on nightfall which occurs some amount of time 42 to 72 minutes, after sunset.
According to Maimonides, nightfall occurs. By the 17th century, this had become three-second-magnitude stars; the modern definition is when the center of the sun is 7° below the geometric horizon, somewhat than civil twilight at 6°. The beginning of the daytime portion of each day is determined both by sunrise. Most halachic times are based on some combination of these four times and vary from day to day throughout the year and vary depending on location; the daytime hours are divided into Sha'oth Zemaniyoth or "Halachic hours" by taking the time between sunrise and sunset or between dawn and nightfall and dividing it into 12 equal hours. The nighttime hours are s