Gregorian_calendar

qas: question: What does duel dating use to show the date?
answers: text: two consecutive years

question: What is the Old Style date mean?
answers: text: Julian calendar

question: What is N.S. stand for?
answers: text: New Style

question: What are New Style dates?
answers: text: Gregorian

question: Why use two consecutive year dates?
answers: text: starting date of the year

question: What is used with dates to determine whether a date is correct or not?

question: What uses two different dates because of a difference in the ending date of the year?

question: Which system indicates that the Gregorian year has been adjusted to start on January 1?

question: Which system indicates that the date that the Julian date has been adjusted for length?
context: To unambiguously specify the date, dual dating or Old Style (O.S.) and New Style (N.S.) are sometimes used with dates. Dual dating uses two consecutive years because of differences in the starting date of the year, or includes both the Julian and Gregorian dates. Old Style and New Style (N.S.) indicate either whether the start of the Julian year has been adjusted to start on 1 January (N.S.) even though documents written at the time use a different start of year (O.S.), or whether a date conforms to the Julian calendar (O.S.) rather than the Gregorian (N.S.).

qas: question: Who revised the Julian calendar?
answers: text: Pope Gregory XIII

question: When was the Gregorian Calendar introduced?
answers: text: 1582

question: What calendar was used in the reform to create the Gregorian calendar?
answers: text: Julian calendar

question: What holiday was the inducement to revise the Julian calendar?
answers: text: Easter

question: When did the First Council of Nicaea rule that Easter be celebrated by all Christians?
answers: text: on the same day

question: What was the Julian calendar a reform of?

question: What calendar was started in the fifteenth century?

question: Which Pope started the Julian calendar?

question: What holiday led to the revision of the Gregorian calendar

question: Who suggested that all Christians celebrate Easter on the same day during the third century?
context: The Gregorian calendar was a reform of the Julian calendar instituted in 1582 by Pope Gregory XIII, after whom the calendar was named, by papal bull Inter gravissimas dated 24 February 1582. The motivation for the adjustment was to bring the date for the celebration of Easter to the time of year in which it was celebrated when it was introduced by the early Church. Although a recommendation of the First Council of Nicaea in 325 specified that all Christians should celebrate Easter on the same day, it took almost five centuries before virtually all Christians achieved that objective by adopting the rules of the Church of Alexandria (see Easter for the issues which arose).

qas: question: What ruler decreed the change to the Gregorian calendar?
answers: text: Philip II of Spain

question: Besides part of Italy, over what areas did Phillip rule?
answers: text: Spain and Portugal

question: What was the first day selected to be the first day using the new calendar?
answers: text: Friday, 15 October 1582

question: What was the last day the Julian calendar was used?
answers: text: Thursday, 4 October 1582

question: Why did the Spanish colonies lag behind in adopting the calendar?
answers: text: delay in communication

question: What King decreed the change from the Gregorian to the Julian calendar?

question: Who was affected by Philip II's switch to the Julian calendar?

question: What changed Julian Thursday, 4 October 1582 to Gregorian Friday, 15 October 1582?

question: What calendar was last used on Friday, October 15 1582?
context: Philip II of Spain decreed the change from the Julian to the Gregorian calendar, which affected much of Roman Catholic Europe, as Philip was at the time ruler over Spain and Portugal as well as much of Italy. In these territories, as well as in the Polish–Lithuanian Commonwealth (ruled by Anna Jagiellon) and in the Papal States, the new calendar was implemented on the date specified by the bull, with Julian Thursday, 4 October 1582, being followed by Gregorian Friday, 15 October 1582. The Spanish and Portuguese colonies followed somewhat later de facto because of delay in communication.

qas: question: When did the last country to adopt the Gregorian calendar start using it?
answers: text: 1923

question: At what date did the first country start using the new calendar?
answers: text: 1582

question: How which calendar did some countries notate the date?
answers: text: in both

question: Who said that English writers usually used both dates on writings?
answers: text: Woolley

question: What difference in dating caused the use of double-dating documents?
answers: text: different beginnings of the year

question: What happened in the fifteenth century that made it necessary to give dates using both calendars?

question: What happened in the nineteenth century the Gregorian calendar that made it necessary to give dates using both calendars?

question: Why was it not necessary to use the dual year when giving two dates?

question: Why did the year sometimes have to be double dated after 1582?

question: What did John Dee note?
context: During the period between 1582, when the first countries adopted the Gregorian calendar, and 1923, when the last European country adopted it, it was often necessary to indicate the date of some event in both the Julian calendar and in the Gregorian calendar, for example, "10/21 February 1750/51", where the dual year accounts for some countries already beginning their numbered year on 1 January while others were still using some other date. Even before 1582, the year sometimes had to be double dated because of the different beginnings of the year in various countries. Woolley, writing in his biography of John Dee (1527–1608/9), notes that immediately after 1582 English letter writers "customarily" used "two dates" on their letters, one OS and one NS.

qas: question: What was the percentsge of correction from the Julian calendar to the new Gregorian calendar?
answers: text: 0.002%

question: What was the correction due to?
answers: text: length of the year

question: What change in date motivated the change in calendars?
answers: text: celebration of Easter

question: To what astrological date was Easter tied?
answers: text: spring equinox

question: What was wrong in the Julian calendar?
answers: text: slightly too long

question: What percentage did the Julian calendar fixed the Gregorian calendar?

question: What was too short in the Julian calendar?

question: What did the spring equinox motivate the church to change?

question: What did the Protestant church considered to be undesirable?

question: What was first adopted by Eastern Orthodox countries
context: The calendar was a refinement to the Julian calendar amounting to a 0.002% correction in the length of the year. The motivation for the reform was to bring the date for the celebration of Easter to the time of the year in which it was celebrated when it was introduced by the early Church. Because the celebration of Easter was tied to the spring equinox, the Roman Catholic Church considered the steady drift in the date of Easter caused by the year being slightly too long to be undesirable. The reform was adopted initially by the Catholic countries of Europe. Protestants and Eastern Orthodox countries continued to use the traditional Julian calendar and adopted the Gregorian reform after a time, for the sake of convenience in international trade. The last European country to adopt the reform was Greece, in 1923.

qas: question: What kind of calendar is the Gregorian calendar?
answers: text: solar

question: How many days are in the Gregorian calendar?
answers: text: 365

question: How often is a leap day added to the Julian calendar year?
answers: text: every 4 years

question: When does the Gregorian calendar omit 3 leap days?
answers: text: every 400 years

question: On what day did both the Julian and Gregorian calendars add leap day?
answers: text: 24 February

question: What calendar is a lunar calendar?

question: When does the Julian calendar omit three leap days?

question: Which church still host festivals on the twenty-third in leap years?

question: What did Julian reform not change about leap year?
context: The Gregorian calendar is a solar calendar. A regular Gregorian year consists of 365 days, but as in the Julian calendar, in a leap year, a leap day is added to February. In the Julian calendar a leap year occurs every 4 years, but the Gregorian calendar omits 3 leap days every 400 years. In the Julian calendar, this leap day was inserted by doubling 24 February, and the Gregorian reform did not change the date of the leap day. In the modern period, it has become customary to number the days from the beginning of the month, and February 29th is often considered as the leap day. Some churches, notably the Roman Catholic Church, delay February festivals after the 23rd by one day in leap years.

qas: question: When was Easter Sunday celebrated after the equinox?
answers: text: 15th day

question: What did churches do to settle the date if there was a difference? 
answers: text: compromise

question: By what century had almost all churches begun celebrating Easter according to the Alexandrian Easter?
answers: text: 10th century

question: On what border of the Byzantine Empire were the last holdouts for celebrating according the  Alexandrian Easter?
answers: text: eastern border

question: What date placement drifted increasingly off the true date on the calendar?
answers: text: vernal equinox

question: What was celebrated on the fifteenth day after the equinox?

question: In what century did all the churches adopt the Alexandrian Easter?

question: Who noticed the equinox drift in the seventh century?

question: What did the Alexandrian Easter place on 25 March?
context: Easter was the Sunday after the 15th day of this moon, whose 14th day was allowed to precede the equinox. Where the two systems produced different dates there was generally a compromise so that both churches were able to celebrate on the same day. By the 10th century all churches (except some on the eastern border of the Byzantine Empire) had adopted the Alexandrian Easter, which still placed the vernal equinox on 21 March, although Bede had already noted its drift in 725—it had drifted even further by the 16th century.

qas: question: What did Lilius first propose to correct in the calendar?
answers: text: length of the year

question: By how much is the Julian calendar too long?
answers: text: 11 minutes

question: How much difference does the extra 11 minutes make over 400 years time?
answers: text: three days

question: On what date was the original vernal equinox set?
answers: text: 21 March

question: By the time of Lilius where was the equinox falling?
answers: text: 10 or 11 March

question: Who proposed lengthening the year?

question: Which year was eleven minutes too short?

question: What causes an extra three days every 400 years in the Gregorian calendar?

question: What was originally set as March 25?

question: What did Gregory propose deleting to correct the ten day drift?
context: Lilius's proposals had two components. Firstly, he proposed a correction to the length of the year. The mean tropical year is 365.24219 days long. As the average length of a Julian year is 365.25 days, the Julian year is almost 11 minutes longer than the mean tropical year. The discrepancy results in a drift of about three days every 400 years. Lilius's proposal resulted in an average year of 365.2425 days (see Accuracy). At the time of Gregory's reform there had already been a drift of 10 days since the Council of Nicaea, resulting in the vernal equinox falling on 10 or 11 March instead of the ecclesiastically fixed date of 21 March, and if unreformed it would drift further. Lilius proposed that the 10-day drift should be corrected by deleting the Julian leap day on each of its ten occurrences over a period of forty years, thereby providing for a gradual return of the equinox to 21 March.

qas: question: On what date did most European countries set the start of the new year?
answers: text: 1 January

question: When did Scotland begin to use January 1 as the start of the new year?
answers: text: 1600

question: When did the other British states and colonies set the year start date to January 1?
answers: text: 1752

question: What act did Britain use to implement the use of the Gregorian calendar?
answers: text: Calendar (New Style) Act 1750

question: When did England finally change the tax year to 6 April?
answers: text: 1800

question: What do most European countries do after they adopted the Gregorian calendar?

question: What country changed the new year to January 1 during the sixteenth century

question: Who changed the start of the new year to January 1 during the seventeenth century?

question: What was the name of the act that changed the start of the year and a seventeenth century?

question: What remained on March 25 in Scotland?
context: Most Western European countries changed the start of the year to 1 January before they adopted the Gregorian calendar. For example, Scotland changed the start of the Scottish New Year to 1 January in 1600 (this means that 1599 was a short year). England, Ireland and the British colonies changed the start of the year to 1 January in 1752 (so 1751 was a short year with only 282 days) though in England the start of the tax year remained at 25 March (O.S.), 5 April (N.S.) till 1800, when it moved to 6 April. Later in 1752 in September the Gregorian calendar was introduced throughout Britain and the British colonies (see the section Adoption). These two reforms were implemented by the Calendar (New Style) Act 1750.

qas: question: Attempting to use Gregorian dates for earlier events  on the Julian calendar should be used with what action?
answers: text: caution

question: When are events usually shown as they appeared on the Julian calendar?
answers: text: prior to 15 October 1582

question: When was the Battle of Agincourt?
answers: text: 25 October 1415

question: What other date is 25 October known for, that keeps the Battle of Agincourt on 25 October,1415?
answers: text: Saint Crispin's Day

question: In the Julian calendar when is the start of the new year?
answers: text: 1 January

question: What can you extend backwards to create an accurate calendar?

question: What events are shown as they appeared on the Julian calendar with the year starting as it did when they occurred?

question: What is the disputed date for St. Crispin's Day?

question: What started in January Julian calendar?
context: Extending the Gregorian calendar backwards to dates preceding its official introduction produces a proleptic calendar, which should be used with some caution. For ordinary purposes, the dates of events occurring prior to 15 October 1582 are generally shown as they appeared in the Julian calendar, with the year starting on 1 January, and no conversion to their Gregorian equivalents. For example, the Battle of Agincourt is universally considered to have been fought on 25 October 1415 which is Saint Crispin's Day.

qas: question: Why would a knuckle -space count be used to determine months?
answers: text: language-independent

question: A knuckle count is a month of how many days?
answers: text: 31

question: The space between knuckles is what kind of month?
answers: text: short month

question: What are held together for a knuckle-space month count?
answers: text: one's two fists

question: What method for determining months is dependent on language?

question: What junction is counted for February?
context: A language-independent alternative used in many countries is to hold up one's two fists with the index knuckle of the left hand against the index knuckle of the right hand. Then, starting with January from the little knuckle of the left hand, count knuckle, space, knuckle, space through the months. A knuckle represents a month of 31 days, and a space represents a short month (a 28- or 29-day February or any 30-day month). The junction between the hands is not counted, so the two index knuckles represent July and August.

qas: question: How many parts did the Gregorian calendar reform have?
answers: text: two parts

question: What was the first reform concerning the calendar?
answers: text: Julian calendar

question: What was the second reform of the calendar?
answers: text: lunar cycle

question: What was calculated using the lunar calendar?
answers: text: date of Easter

question: What did Lilius's calendar plan to reduce in every 400 years?
answers: text: number of leap years

question: How many parts did the Gregorian reform have?

question: What calendar was changed by the Julia reform?

question: What reform change the lunar cycle used by pagans?

question: Who oppose the proposal for the reform?

question: Whose reform included increasing the number of leap years and for centuries?
context: The Gregorian reform contained two parts: a reform of the Julian calendar as used prior to Pope Gregory XIII's time and a reform of the lunar cycle used by the Church, with the Julian calendar, to calculate the date of Easter. The reform was a modification of a proposal made by Aloysius Lilius. His proposal included reducing the number of leap years in four centuries from 100 to 97, by making 3 out of 4 centurial years common instead of leap years. Lilius also produced an original and practical scheme for adjusting the epacts of the moon when calculating the annual date of Easter, solving a long-standing obstacle to calendar reform.

qas: question: What calendar did Turkey use before 1917 for general purposes?
answers: text: lunar Islamic

question: What calendar did Turkey utilize for fiscal purposes?
answers: text: Julian

question: Where did Turkey start the fiscal year?
answers: text: 1 March

question: When did Turkey begin to use the Gregorian calendar for fiscal means?
answers: text: 1 March 1917

question: When did Turkey start using the Gregorian calendar for all purposes?
answers: text: 1 January 1926

question: Who use the lunar Islamic calendar until the nineteenth century?

question: Who use the Hegira era is a fiscal calendar?

question: What was used to set the year number?

question: What was needed because the lunar year is longer than the solar year?

question: What did Turkey start using for all purposes on March 1, 1917?
context: Prior to 1917, Turkey used the lunar Islamic calendar with the Hegira era for general purposes and the Julian calendar for fiscal purposes. The start of the fiscal year was eventually fixed at 1 March and the year number was roughly equivalent to the Hegira year (see Rumi calendar). As the solar year is longer than the lunar year this originally entailed the use of "escape years" every so often when the number of the fiscal year would jump. From 1 March 1917 the fiscal year became Gregorian, rather than Julian. On 1 January 1926 the use of the Gregorian calendar was extended to include use for general purposes and the number of the year became the same as in other countries.

qas: question: How many days do you subtract to convert days from a calendar?
answers: text: subtract one day

question: What does one need to remember about  the date of February 29 in the Julian calendar?
answers: text: February 29 is discounted

question: If you need a date of four days less, what do you subtract from the Julian calendar?
answers: text: -4

question: How many days you add to convert days from a calendar?

question: What is discounted when converting from Gregorian to Julian?

question: What you add to move from the Julian calendar to the Gregorian calendar?
context: Up to February 28 in the calendar you are converting from add one day less or subtract one day more than the calculated value. Remember to give February the appropriate number of days for the calendar you are converting into. When you are subtracting days to move from Julian to Gregorian be careful, when calculating the Gregorian equivalent of February 29 (Julian), to remember that February 29 is discounted. Thus if the calculated value is -4 the Gregorian equivalent of this date is February 24.

qas: question: What is the difference in time between the calendars?
answers: text: 10 minutes 48 seconds

question: With what other difference did the Gregorian calendar concern itself?
answers: text: accumulated difference

question: When was the vernal equinox at the end of the third century?
answers: text: 20 March or 21 March

question: In order to account for the full moon coming after the equinox, when was the equinox set?
answers: text: 22 March

question: How did the Gregorian calendar set these same of the full moon not preceding Easterconditions?
answers: text: removing ten days

question: What changed the length of the calendar year from 365.2425 days to 365.25 days?

question: What was reduced by forty-eight minutes and ten seconds?

question: What was devised during the 300s

question: What was not to follow the equinox?

question: What was March 22 the latest date for?
context: In addition to the change in the mean length of the calendar year from 365.25 days (365 days 6 hours) to 365.2425 days (365 days 5 hours 49 minutes 12 seconds), a reduction of 10 minutes 48 seconds per year, the Gregorian calendar reform also dealt with the accumulated difference between these lengths. The canonical Easter tables were devised at the end of the third century, when the vernal equinox fell either on 20 March or 21 March depending on the year's position in the leap year cycle. As the rule was that the full moon preceding Easter was not to precede the equinox the equinox was fixed at 21 March for computational purposes and the earliest date for Easter was fixed at 22 March. The Gregorian calendar reproduced these conditions by removing ten days.

qas: question: When did the Council of Trent agree to the corrected calendar?
answers: text: 1563

question: To what time did the Council require the date of the vernal equinox to be set?
answers: text: 325

question: What did mathematicians of the time want to use to set the date of Easter?
answers: text: motions of the sun and moon

question: What method was used instead of computations of the sun and moon?
answers: text: tabular method

question: Whose modified proposal was adopted?
answers: text: Aloysius Lilius

question: What plan to the Council of Trent approve in the fifteenth century?

question: What did the first Council of Nicaea require to be restored to the one set in 325?

question: What did the first Council of Nicaea require alterations for?

question: What was sent to mathematicians in the fifteenth century?

question: What was adopted from the proposal of Moleto
context: The Council of Trent approved a plan in 1563 for correcting the calendrical errors, requiring that the date of the vernal equinox be restored to that which it held at the time of the First Council of Nicaea in 325 and that an alteration to the calendar be designed to prevent future drift. This would allow for a more consistent and accurate scheduling of the feast of Easter. In 1577, a Compendium was sent to expert mathematicians outside the reform commission for comments. Some of these experts, including Giambattista Benedetti and Giuseppe Moleto, believed Easter should be computed from the true motions of the sun and moon, rather than using a tabular method, but these recommendations were not adopted. The reform adopted was a modification of a proposal made by the Calabrian doctor Aloysius Lilius (or Lilio).

qas: question: When were the rights to publish the calendar granted?
answers: text: 3 April 1582

question: Who awarded the rights to publish the calendar?
answers: text: the pope

question: What problem caused the papal brief granting the right to publish to be withdrawn?
answers: text: demand for copies

question: When were the rights to print the calendar withdrawn?
answers: text: 20 September 1582

question: Where were the first calendars printed?
answers: text: Rome

question: Who decreed the reform during the fifteenth century?

question: What was Luigi Lilio given exclusive rights to?

question: Why was a new brief granted in September 2015 eighty-two?September
context: A month after having decreed the reform, the pope with a brief of 3 April 1582 granted to Antonio Lilio, the brother of Luigi Lilio, the exclusive right to publish the calendar for a period of ten years. The Lunario Novo secondo la nuova riforma printed by Vincenzo Accolti, one of the first calendars printed in Rome after the reform, notes at the bottom that it was signed with papal authorization and by Lilio (Con licentia delli Superiori... et permissu Ant(onii) Lilij). The papal brief was later revoked, on 20 September 1582, because Antonio Lilio proved unable to keep up with the demand for copies.

qas: question: What year did the Roman Republic use for dates?
answers: text: consular year

question: What event started the consular year?
answers: text: consuls first entered office

question: What was the date of the consular year before 222 BC?
answers: text: 1 May

question: What was the date of the start of the consular year from 222 BC?
answers: text: 15 March

question: When did Rome begin to use the Julian calendar?
answers: text: 45 BC

question: What was used as the year in the early Roman church?

question: What calendar came into use in 153 BC?

question: During what period did a year used for dates not change?

question: What was marked by the date the Emperor took office?
context: The year used in dates during the Roman Republic and the Roman Empire was the consular year, which began on the day when consuls first entered office—probably 1 May before 222 BC, 15 March from 222 BC and 1 January from 153 BC. The Julian calendar, which began in 45 BC, continued to use 1 January as the first day of the new year. Even though the year used for dates changed, the civil year always displayed its months in the order January to December from the Roman Republican period until the present.

qas: question: What other system of calculations are inherent in the Gregorian calendar?
answers: text: system of weeks

question: Why is calculating the days of the Gregorian calendar not simple?
answers: text: irregularities

question: After each country adopted the calendar how did the weekly cycle continue?
answers: text: uninterrupted

question: What was the date of adoption for the calendar?
answers: text: Friday, 15 October 1582

question: What was the previous day's date by the Julian calendar?
answers: text: Thursday, 4 October 1582

question: What is simple to do using the Gregorian system?

question: What makes Calgary the days of the week symbol in the Gregorian system?

question: What was interrupted when the Gregorian calendar was adopted in each country?

question: What ended on Friday, October 5 1582?
context: In conjunction with the system of months there is a system of weeks. A physical or electronic calendar provides conversion from a given date to the weekday, and shows multiple dates for a given weekday and month. Calculating the day of the week is not very simple, because of the irregularities in the Gregorian system. When the Gregorian calendar was adopted by each country, the weekly cycle continued uninterrupted. For example, in the case of the few countries that adopted the reformed calendar on the date proposed by Gregory XIII for the calendar's adoption, Friday, 15 October 1582, the preceding date was Thursday, 4 October 1582 (Julian calendar).

qas: question: Who thought that the seasonal drift in the date of Easter unacceptable?
answers: text: Roman Catholic Church

question: What even is tired to the date for Easter?
answers: text: spring equinox

question: What did the Church of Alexandria use to calculate the date of Easter?
answers: text: Metonic cycle

question: Where did the Church of Alexandria place the vernal equinox?
answers: text: 21 March

question: Until 342 when did the Church of Rome think the vernal equinox fell?
answers: text: 25 March

question: Who found the drifting and the date of the spring equinox unacceptable?

question: What did the church of Rome use the metonic cycle to determine?

question: What did the church of Alexandria place on March 25?

question: What did the Church of Rome place on 21 March
context: Because the spring equinox was tied to the date of Easter, the Roman Catholic Church considered the seasonal drift in the date of Easter undesirable. The Church of Alexandria celebrated Easter on the Sunday after the 14th day of the moon (computed using the Metonic cycle) that falls on or after the vernal equinox, which they placed on 21 March. However, the Church of Rome still regarded 25 March as the equinox (until 342) and used a different cycle to compute the day of the moon. In the Alexandrian system, since the 14th day of the Easter moon could fall at earliest on 21 March its first day could fall no earlier than 8 March and no later than 5 April. This meant that Easter varied between 22 March and 25 April. In Rome, Easter was not allowed to fall later than 21 April, that being the day of the Parilia or birthday of Rome and a pagan festival.The first day of the Easter moon could fall no earlier than 5 March and no later than 2 April.

qas: question: Who was the architect of the Gregorian calendar?
answers: text: Christopher Clavius

question: What did the architects of the calendar notice about the astronomical tables?
answers: text: discrepancies

question: Whose solution to the discrepancies of the tables would have been agreeable to astronomers?
answers: text: Petrus Pitatus

question: When did Pitatus offer his solution to the leap year problem?
answers: text: 1560

question: What is the theory about leap year called?
answers: text: Gregorian leap year rule

question: What provided the sons mean latitude?

question: Who noticed that the tables agreed on the time the sun passed the vernal equinox?

question: Who suggested ninety-seven leap years in 400 years during the fifteenth century

question: Who solution to discrepancies in the tables was not agreeable to astronomers?

question: What calendar did Pitatus create?
context: Ancient tables provided the sun's mean longitude. Christopher Clavius, the architect of the Gregorian calendar, noted that the tables agreed neither on the time when the sun passed through the vernal equinox nor on the length of the mean tropical year. Tycho Brahe also noticed discrepancies. The Gregorian leap year rule (97 leap years in 400 years) was put forward by Petrus Pitatus of Verona in 1560. He noted that it is consistent with the tropical year of the Alfonsine tables and with the mean tropical year of Copernicus (De revolutionibus) and Reinhold (Prutenic tables). The three mean tropical years in Babylonian sexagesimals as the excess over 365 days (the way they would have been extracted from the tables of mean longitude) were 14,33,9,57 (Alphonsine), 14,33,11,12 (Copernicus) and 14,33,9,24 (Reinhold). All values are the same to two places (14:33) and this is also the mean length of the Gregorian year. Thus Pitatus' solution would have commended itself to the astronomers.

qas: question: What designation was added to British dates to differentiate them from countries not using the new calendar? 
answers: text: "Old Style" (OS) and "New Style"

question: When was the Calendar act enacted?
answers: text: 1750

question: With what did the Calendar Act align the British calendar?
answers: text: Gregorian calendar

question: What did the use of Old Style and New Style cause?
answers: text: confusion

question: What law did the British make to cause the use of the Gregorian calendar?
answers: text: Calendar Act of 1750

question: Why are old-style new style not using the British Empire?

question: What did the calendar after 1752 to clarify the meaning of old-style new style?

question: What did the calendar act aligned with the British calendar?

question: What this OS indicate January 1 is?
context: "Old Style" (OS) and "New Style" (NS) are sometimes added to dates to identify which system is used in the British Empire and other countries that did not immediately change. Because the Calendar Act of 1750 altered the start of the year, and also aligned the British calendar with the Gregorian calendar, there is some confusion as to what these terms mean. They can indicate that the start of the Julian year has been adjusted to start on 1 January (NS) even though contemporary documents use a different start of year (OS); or to indicate that a date conforms to the Julian calendar (OS), formerly in use in many countries, rather than the Gregorian calendar (NS).

qas: question: The Gregorian calendar is an improvement over what other calendar?
answers: text: Julian

question: How many days must be skipped to align the calendar with mean solar days in a year?
answers: text: three Julian leap days

question: What is the approximate error for every 3,300 years?
answers: text: one day

question: What is the error rate of the vernal equinox per every 7,700 years?
answers: text: 1 day

question: What was the error rate in the Julian calendar?
answers: text: 1 day in 128 years

question: How does Julian calendar improve the approximations made by the Gregorian calendar?

question: How many years does it take for the Julian approximation to have an error of one day?

question: In the Julia system what is the error rate for the vernal equinox first 7700 years?

question: The Julian system skips three leap days and how many years?
context: The Gregorian calendar improves the approximation made by the Julian calendar by skipping three Julian leap days in every 400 years, giving an average year of 365.2425 mean solar days long. This approximation has an error of about one day per 3,300 years with respect to the mean tropical year. However, because of the precession of the equinoxes, the error with respect to the vernal equinox (which occurs, on average, 365.24237 days apart near 2000) is 1 day every 7,700 years, assuming a constant time interval between vernal equinoxes, which is not true. By any criterion, the Gregorian calendar is substantially more accurate than the 1 day in 128 years error of the Julian calendar (average year 365.25 days).