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Omar Khayyam Leads Persian Calendar Reform (1079)

Type Event Region West Asia Time 1079

Around 1079 CE, Seljuk Sultan Malik Shah I convened astronomers in Isfahan, with Omar Khayyam leading the creation of a new calendar (later called th…

Timeline

  1. c. 1074–1075Isfahan court · IranTo improve the official calendar and agricultural scheduling, Malik Shah I established an astronomical observatory and calendrical office in Isfahan, convening scholars including Omar Khayyam for long-term observations.
  2. 1079Isfahan · IranDrawing on years of sundial and star-table observations, the commission set a cycle of 8 leap years in 33, producing a more precise new calendar implemented across the empire, later known as the Jalali calendar.

Sources