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The Status of the Metric in the United States Strictly speaking, the US has been "metric" since the Mendenhall Order, issued in 1893. The inch is defined as exactly 2.54 centimeters, the pound (mass) is exactly 0.45359237 kilograms, the pound force is exactly 4.4482216152605 newtons, and so on. The conversion factors have changed a bit since 1893, but that ...


43

Edit: As pointed out in the comments, I realize this answer doesn't deal with the history of metrication in America. I intended it only as an answer to "why does the US keep using their systems?" However, other answers here do a very good job outlining the history, and I encourage everyone to check those out too. As a non-American, I've always found it ...


24

Suetonius has this to report about Tiberius, the second emperor and the third Caesar: [H]e at first played a most unassuming part, almost humbler than that of a private citizen. Of many high honours he accepted only a few of the more modest. He barely consented to allow his birthday, which came at the time of the Plebeian games in the Circus, to be ...


21

In general, dating was complicated, and different conventions existed simultaneously in England at that time. For the specific example of William the Conqueror's coronation, we have different sources within the following decades implying that it was in 1066 or 1067, anno Domini. The precision sought in the question did not exist, at least in the same form ...


20

With regard to imperial measurement, there is actually an interesting reason (at least in my opinion) why the US was not an early adopter of it. Thomas Jefferson had actually developed his own base-10 system of measurement (I believe he even attempted a base-10 system of time), and, had US relations been better with post-Revolution France, we may well have ...


19

It wasn't simple to track time at night until the invention of mechanical clocks. Before that the breakpoint between days was sunrise (early Roman), solar midnight (later Roman), or sunset (Athenians, Jews) depending on the area and period. Also worth noting is that until mechanical clocks the length of hours would also vary from a day to the next, and time ...


18

Essentially the extra quarter of a day that the Julian leap year added was slightly longer than the 0.242 of a day left over in the actual solar year. It affected Pope Gregory XIII because the Christian holidays were being celebrated on the wrong days. This was noticed by the Pope's astronomers and prompted the need for change. What's the science behind ...


18

The ancient Romans used to have the new year at the end of February. To fit the lunar and solar calendars, an extra month was sometimes added after February. This practice continued even after the months were shifted so that new year moved to where it is now (this shift is the reason why we have e.g. "december" 'tenth month', as number twelve). This proved ...


17

We have an enormous amount of evidence for the ancient Babylonian calendar, but no evidence at all for a seven-day week in ancient Babylonia. In the ancient world there were two forms of the seven-day week. First, the Jewish week (eventually adopted by Christians and Muslims) has numbered days from one (Sunday) to six (Friday) and the Sabbath on the seventh ...


16

The short answer is because the Japanese government does not designate the old lunisolar new year as a public holiday. Officially, China does in fact celebrate New Year's Day (元旦) on the Western (Gregorian) 1 January. In contrast, the traditional lunar new year is a public holiday named Spring Festival (春节). Since the latter is a longer holiday, combined ...


16

For the most part, church and celestial events. In particular, midsummer and midwinter and the equinoxes were both easy to detect and were important events, at least in the colder climates of Europe. One problem with this approach was that the Julian calendar, which was used pretty much everywhere during the middle ages, by the 1500s had gotten seriously ...


15

The Jewish calendar is in year 5774 (between September of 2013 and October of 2014, it's a leap year), so the "Jewish civilization" is not in 2014. The state of Israel, which is really the only official body to recognize the Jewish calendar, determines all of its holidays and memorial days on the basis of the Jewsih calendar. However, all of the civil dates ...


15

I am not sure about legends (are there any specifying Rome's foundation year? I suspect it might be in the form of "X years since the sack of Troy"). But since your question also asked about "ancient Roman scholars" and "ancient Roman sources"... During most of the Roman Republic, years were named based on who had been elected to the consulship for that ...


14

Some astronomical events, viz. eclipses, can be reliably predicted to the day. I think they are the best method to identify a date exactly. This webpage provides some insight on the topic. It is basically a list of recorded solar eclipses, where the first one would be on 22 March 2134 BCE. There is however some uncertainty about whether or not the event ...


14

Actually several did: Caligula renamed September to Germanicus (Suetonius, Caligula, 15) in memory of his father. Nero renamed April to Neronium (Suetonius, Nero, 55).


13

No major Orthodox Church follows the Gregorian calendar. Most follow the Milanković calendar (the "new calendar"), and the Russian, Serbian and Georgian Orthodox Churches, and the Greek Orthodox Church of Jerusalem follow the Julian calendar (the "old calendar"). The monasteries in Mount Athos follow the Julian calendar for religious issues, and the ...


13

First, the answer to your second question. [W]ho invented that calender? The current calendar that most of the western world uses is Gregorian Calendar1, which is an improvement over Julian Calendar, which itself was an improvement over Traditional Roman Calendar. Now, on to the first question. Generally months with 31 and 30 days come in alternate ...


13

In the 1970s the day numbering was standardized worldwide, culminating in an UN decision. The current version of the standard is ISO 8601. Some countries were more timely than others in adopting this standard. In Christian interpretation the day after Sabbath (i.e. Sunday) was seen as the first day of the week (e.g. chapter 16 of the Gospel of Mark). Early ...


12

After some reading about the early Roman Calendar, it is relevant to note that originally the calendar had only ten months and began on March, with an uncounted “winter” period after December. The number of days on each month were more or less flexible, and they usually tried to align the 15th of March, the mid of the month, with Ides, a full moon. At the ...


12

Not that I know of, but in 1712 in Sweden, February had 30 days. Sweden, being a Protestant country, was initially suspicious of the "papist" Gregorian calendar, but decided to adopt it in the early 18th century. However, there was an idea to do so gradually, by simply skipping all the leap days until the calendars were in synch. This was done in 1700, but ...


11

The Gregorian calendar, Western calendar or the Christian calendar, is a calendar that was a reform in 1582 to the Julian calendar. It was introduced by Pope Gregory XIII, after whom the calendar was named. But was is an adaptation of a calendar designed by Italian doctor, astronomer and philosopher Luigi Lilio. And it is not nesassarly based of Jesus birth ,...


11

I'm afraid the answer is that we don't know. The Romans gradually replaced their 8 day week (the imperial nundinal cycle) with a 7 day week over a course of a century, after Julius Caesar's calendar reform in 46 BC. Their reasons for doing so are unclear, however we do know that the two cycles co-existed for quite some time. Ultimately, the nundinal cycle ...


11

The term you're looking for is chronology (Wikipedia's article on the subject is rather sub-par). In general, there are two major ways of synchronizing dates. Find an event recorded in more than one calendar. For example, if a treaty was signed on "a.d. VIII Kal. Oct, Julius et Caesar consulibus" and "7.14.19.11.14", you can establish an equivalence ...


10

It was due to the Second Celtiberian War. In 154 BC, there was rebellion in Spain. Quintus Fulvius Nobilior was designated consul for the following year but could not assume office until the Ides of March. Given the military situation, the Senate decreed January 1 to be the start of the new civil year, which permitted Nobilior to be inducted and depart ...


10

A modern secondary historical paper or book should always use the Gregorian Calendar and the era of Exiguus. For pre-Gregory dates the proleptic calendar should be used. The reason for this is so that the exact distance between two dates can always be calculated easily and so that all books are using the same time scale so that dates in one book can easily ...


10

The original Roman calendar is believed to have been a lunar calendar, which may have been based on one of the Greek lunar calendars. As the time between new moons averages 29.5 days, its months were constructed to be either hollow (29 days) or full (30 days). KING ROMULUS - The original Roman calendar was said to have been invented by Romulus, the first ...


9

My answer is more about the metric system then about dates. About dates, also consider that there are Chinese, Hebrew and Islamic calendar, which are much more different from the Christian one. According to Wikipedia: In 1866, Congress authorized the use of the metric system and supplied each state with a set of standard metric weights and measures. ...


9

This is covered by Bonnie Blackburn and LeoFranc Holford-Strevens in their book The Oxford Companion to the Year: An exploration of calendar customs and time-reckoning (1999, reprinted with corrections 2003, p. 671). They call the method we use today the "forward count". The forward count begins to be attested in the fifth century, and makes greater inroads ...


9

The change over to the Gregorian Calendar happened over a period of over 300 years across the western world. Consequently the number of skipped days varied by country depending on when they changed over (the longer they left it, the more days needed to be skipped). However, the skip only affected the calendar date and not the day of the week. So for example,...


9

Of course it depends whose months you look at. Part of the decimalization project in revolutionary France was Claude Boniface Collignon's proposals for decimalizing time. He called for ten "solar months" per year, each of 36.5 days. See page 168 of his Decouverte d'etalons justes, naturels, invariables et universels. I think his long months only exist ...


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