Talk:Q1048

Change English title?

En-wiki goes for Julius Caesar (no ligature), so perhaps the title should be "Caesar" here, and "Cæsar" moved to the AKA section? It Is Me Here ^{t / c} 10:50, 20 February 2013 (UTC)

Date of death

I have added a reference for the date of death. (A book, not merely marking it as imported from one of the Wikipedias. In Wikidata, dates before the firm establishment of the Julian calendar are understood to be in the proleptic Julian calendar (Q1985786). Leap years were not properly implemented in the first few decades of the Julian calendar, and surviving records are not good enough to extend the proleptic Julian calendar before AD 8. Therefore I've changed the precision from day to month. Jc3s5h (talk) 14:14, 19 September 2016 (UTC)

Incorrect date of birth

I have marked the date of birth, 101 Gregorian, because it is widely known that Caesar lived in the first century before Christ. Jc3s5h (talk) 14:01, 30 September 2018 (UTC)

Precision of birth and death date

I have reduced the precision of the birth date in this edit by User:Jarekt. It was "day", I changed it to "month". The date given, 13 July 100 BCE, is in the Roman calendar. The surviving records do not provide enough information to accurately convert between the Roman calendar and the proleptic Julian calendar. The proleptic Julian calendar is one of the two supported by Wikidata software, the other is the proleptic Gregorian calendar. There is no support for the Roman calendar, and unless there is a massive find of lost ancient documents, there never will be. Jc3s5h (talk) 05:27, 8 February 2019 (UTC)

Jc3s5h I am not sure which reference you follow about the roman calendar bit, but you should separate statement about it. According to https://books.google.com/books?id=oR-ljeBaWIcC&pg=PA30#v=onepage&q&f=false "Caius Julius Caesar was born on 13 July 100 BCE according to the modern calendar. " and footnote in https://books.google.com/books?id=9Q83DAAAQBAJ&pg=PA194#v=onepage&q&f=false says something equivalent. According to w:en:Roman_calendar#Months, roman calendar did not have month called "July". Any dates using modern month names follow julian or gregorian calendars, where dates from earlier calendars are mapped to those 2. --Jarekt (talk) 13:26, 8 February 2019 (UTC)

In Blackburn and Holford-Strevens book The Oxford Companion to the Year (1999, reprinted with corrections 2003) page 670, the authors describe points in time where records of solar eclipses allow Roman calendar dates to be compared to modern calendars. "In 190 BC the solar eclipse that according to modern astronomers fell on 14 March was recorded on a.d V Eid Quint., or 11 July....by 168 BC, when the solar eclipse of 21 June was observed on a.d. III Non. Sept. or 3 September". It's possible that due to the proximity to a recorded solar eclipse, it is possible to pin down the date of Julius's birth. Can you provide a source for your assertion "Any dates using modern month names follow julian or gregorian calendars, where dates from earlier calendars are mapped to those 2"? Jc3s5h (talk) 14:01, 8 February 2019 (UTC)

My last sentence was based on reading en:Roman_calendar#Conversion_to_Julian_or_Gregorian_dates, but I truly do not know much about roman calendars. The date of Caesar birth I copied from Caesar, Life of a Colossus (Q24963317), which is a secondary source, but I do not know the primary sources for process of how historians that established that date mapped historical records to "modern calendar". History of the Roman People seems to corroborate 13 July date. --Jarekt (talk) 16:20, 8 February 2019 (UTC)

I take exception to you stating the date of death with a precision of 1 day. For a fuller description, read the coverage of the Julian calendar in Blackburn and Holford-Strevens or other similar sources. Unless you can prove other wise, I presume all the sources you mentioned were giving the date in the Julian calendar as actually observed in Rome. That date was indeed 15 March 44 BC using modern month names and year numbering. But that isn't the calendar that Wikidata uses; Wikidata uses the proleptic Julian calendar, which begins at some point in the middle ages where the correspondence between calendar dates and physical reality can be proven beyond doubt, and applies the rules of the calendar backward to date events. Because the leap year rule established by Julius was misunderstood, sometimes applying a leap year every 3 years instead of every 4, the conversion of dates before 1 March AD 8 is uncertain by a few days. We cannot state with certainty that 15 March 44 BC Julian calendar is the same day as 15 March 44 BC proleptic Julian calendar. Jc3s5h (talk) 18:44, 8 February 2019 (UTC)

Jc3s5h, I do not know much about calendars, I just copy statements from references, following m:The no original research policy. Wikipedia, and by extension Wikidata, is a tertiary source, reporting what other reported. If some reported fact is now believed to be wrong or inaccurate than we still report it but with "depreciated rank". I did not run into any sources yet that dispute date of death, but if you find one please include it. --Jarekt (talk) 19:05, 8 February 2019 (UTC)

As the reader of a reliable source, it is your duty to understand what calendar the source is using. Ordinarily historical sources about Europe and the parts of Africa and Asia under Roman influence would use the Julian calendar as observed in Rome; the dates from the primary sources can simply be translated from Latin and, where necessary, use modern English month names. Astronomers, on the other hand, who need a calendar that can be rigorously converted to modern calendars so that their celestial mechanics calculations come out right, are more likely to use the proleptic Julian calendar.

You have not proved that the sources mentioned use the proleptic Julian calendar. Indeed, the fame of the phrase "the ides of March" strongly suggests this the date as observed in Rome and made famous by all the talking and writing that occurred immediately after the assassination, not a date that was calculated later by scholars who would have been working at about 50 years later, when Augustus decided to straighten out the errors that had crept into the calendar. Bear in mind that the proleptic Julian calendar is calculated starting in the middle ages and working backward, so all the uncertainties between 44 BC and AD 8 add to the uncertainty of the date.

Also bear in mind that it is impossible to enter a Julian calendar date into Wikidata before 1 March AD 8. Wikidata only supports the proleptic Julian calendar and the prolepic Gregorian calendar. The proleptic Julian calendar is identical to the Julian calendar beginning 1 March AD 8. The proleptic Gregorian calendar is identical to the Gregorian calendar beginning 15 October 1582 in the countries that adopted it at the earliest possible date.

I will restore the precision to month. Jc3s5h (talk) 01:36, 9 February 2019 (UTC)

One more comment: perhaps your are confused by the word "Julian" that appears at various places in the user interface. Maybe you think it means Julian calendar. It doesn't. If you read Help:Dates you will see that it really means proleptic Julian calendar (Q1985786). Jc3s5h (talk) 02:14, 9 February 2019 (UTC)

A general note: the statements should reflect the actual information in the source. --- Jura 08:16, 10 February 2019 (UTC)

┌────────────────────────────────────────────────────────────────────────────────────────────────────┘Indeed, the statements should reflect the actual information in the source, to the extent the Wikidata datatype is capable of doing so. If no Wikidata datatype is available that precisely matches the information in the source, and no exact conversion is possible the information in Wikidata will have to be less precise than the source. Deciding what the actual information in the source is may involve a bit of research, such as checking the preface or appendix of a book to see if it has a statement about what calendar was used. This may be impossible when consulting extracts of a book in Google, where important caveats may be in a part of the book not made available by Google. Jc3s5h (talk) 13:17, 10 February 2019 (UTC)