How can I get the Julian birth or death date for someone who was born or died under the Julian Calendar (Isaac Newton, for example) on Wikidata using a SPARQL query?

This simple query returns "4 January 1643," which is Newton's Gregorian birth date:

SELECT ?birthdate WHERE { wd:Q935 wdt:P569 ?birthdate . }

I've Googled (and DDGed) this up and not come up with an answer. Any help you could offer would be great.



As of April 2018, there is no way (in SPARQL).

The RDF Dump format says:

Note that the calendar model is the original values calendar model even if wikibase:timeValue was converted to Gregorian.

Try this query:

  wd:Q935 p:P569 [ wikibase:rank ?rank ;
                   ps:P569       ?simplevalue ;
                   psv:P569      [ wikibase:timeCalendarModel ?calendar ; 
                                   wikibase:timeValue         ?value     ]

As you can see, there are two statements (one of them is not truthy), but the value is 4 January 1643 independently of the calendar model.

           rank             simplevalue      calendar          value      
 ------------------------ ---------------- ------------- ---------------- 
  wikibase:NormalRank      4 January 1643   wd:Q1985727   4 January 1643  
  wikibase:PreferredRank   4 January 1643   wd:Q1985786   4 January 1643

By the way, Wikidata API returns two different dates:

  1. "value": {
              "time": "+1643-01-04T00:00:00Z",
              "timezone": 0,
              "before": 0,
              "after": 0,
              "precision": 11,
              "calendarmodel": "http://www.wikidata.org/entity/Q1985727"
  2. "value": {
              "time": "+1642-12-25T00:00:00Z",
              "timezone": 0,
              "before": 0,
              "after": 0,
              "precision": 11,
              "calendarmodel": "http://www.wikidata.org/entity/Q1985786"

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