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Speculative theory

Thirteen Month CalendarAtlas

Conventions & Standards · Timekeeping & calendars

Calendar reform literature has included affirmative discussion of adopting a thirteen-month year structure. Some religious calendar teachings contrast twelve-month and thirteen-month year models and present a thirteen-month pattern as tied to a creation or scriptural calendar.

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Timeline

  1. 1900 · popularizationModern thirteen-month calendar reform discussions and affirmative briefs
  2. 1920 · amplificationCalendar reform movements catalogued in thirteen-month chronology materials
  3. 1930 · document_releaseJulia E. Johnsen thirteen-month calendar compilation circulated in reform literature
  4. 1980 · document_releaseFisher Calendar art on thirteen-unit calendar themes published
  5. 2001 · first_appearanceEthiopian/Amharic thirteen-month calendar tradition in use
  6. 2021 · document_releaseCreator’s Calendar site publishes multi-year twelve- versus thirteen-month calendar materials
  7. 2023 · amplificationNKENNE feature on Amharic thirteen-month calendar published

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