{
  "name": "Three Gregorian switch dates, with sources",
  "desc": "Three switches from the Julian to the Gregorian calendar, one per row: the papal schedule of 1582, France in December 1582, and Britain and its colonies in September 1752, each with the area it covers, its source and the kind of source.",
  "lic": "CC BY 4.0",
  "lic_url": "https://creativecommons.org/licenses/by/4.0/",
  "by": "The Yardstick Almanac",
  "url": "https://theyardstickalmanac.com/calendars/old-style-new-style-dates/",
  "from": [
    "Explanatory Supplement to the Astronomical Almanac, ch. 15, sec. 15.1.10, 15.3.4, 15.3.5, 15.4.1, 15.4.2 (single values only; read 2026-11-01)",
    "Archives départementales de la Côte-d'Or, B 12083, transcription of the 1582 edict (facts only; read 2026-11-01)",
    "Calendar (New Style) Act 1750, preamble and section 1 (legislation.gov.uk, Open Government Licence v3.0; read 2026-11-01)"
  ],
  "how": "Compiled by The Yardstick Almanac from the data listed",
  "data_by": [
    "Explanatory Supplement sec. 15.4.1 (single value), Côte-d'Or archives B 12083 (facts) and Calendar (New Style) Act 1750 s. 1 (Open Government Licence v3.0); consecutive days checked 2026-11-01, CC BY 4.0"
  ]
}