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Speculative theory
Gregorian calendar impositionAtlas
Conventions & Standards · Timekeeping & calendars
The Gregorian calendar was introduced as a reform of the Julian calendar to correct drift relative to the solar year and the date of the spring equinox. Some communities framed calendar change as an illegitimate religious or political imposition and resisted or delayed compliance.
Open the caseDocumented7
- Documented · Britain and its American colonies switched civil dating in the mid-eighteenth century, advancing the calendar by eleven days.
- Documented · Catholic polities generally adopted the new calendar earlier than many Protestant and Orthodox jurisdictions.
- Documented · Delayed national adoptions produced temporary dual dating and cross-border date mismatches in diplomacy, trade, and record-keeping.
- Documented · Implementation of the reform required skipping a block of calendar days in adopting jurisdictions to realign the civil date with the equinox.
- Documented · Several Orthodox-majority states retained Julian liturgical or civil reckoning long after Catholic and Protestant Europe had switched.
- Documented · The Gregorian calendar was introduced as a reform of the Julian calendar to correct drift relative to the solar year and the date of the spring equinox.
- Documented · The reform adjusted the leap-year rule so that century years are leap years only when divisible by 400.
Official1
- Official · The Gregorian calendar later became the dominant international civil calendar through state adoption and global administrative practice.
Contested1
- Contested · Some communities framed calendar change as an illegitimate religious or political imposition and resisted or delayed compliance.