The Jalali calendar reform

التقويم الجلالي بأمر ملكشاه

between 1074 and 1075 CE · 467 AH – between 1074 and 1075 CE · 467 AH

Isfahan

Sultan Malik-Shah charged Umar Khayyam and a team of astronomers with reforming the calendar; at the Isfahan observatory they produced the Jalali calendar about 467/1079 1.

Depth

At a glance

Era
The Buyid, Fatimid and Seljuk Era
Region
Persia & Central Asia
Review
Draft Completeness 2/5 · Help complete it

In time

1060107010801090
The Buyid, Fatimid and Seljuk Era

In space

Isfahan

Map: Natural Earth, public domain · places and route from the graph

The long-form text for this entry has not been written yet. The facts and connections below come from the museum's data.

Connections

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Had participant
Umar Khayyam
Occurred at
Isfahan

People and things also explored

Jameh Mosque of Isfahan· Conquest of Isfahan (21 AH)· death of al-Bahlawan — the Isfahan mazhab wars, the Rayy fitna, Tughril breaks free· Khayyam's algebra treatise· The killing of Mardawij ibn Ziyad· Mas'ud ibn Mahmud Storms Isfahan· Sultan Muhammad ibn Malikshah takes the Batiniyya fortress at Isfahan and kills Ibn Attash in 500· Mungli killed; Aghlamish inherits his domains

Sources

  1. Mawsu'at A'lam al-Ulama' wa-l-Adaba' al-Arab wa-l-Muslimin — Dar al-Jil / ALECSO
Cite this page

islam.museum contributors. “The Jalali calendar reform”. islam.museum, https://islam.museum/en/event/jalali-calendar-reform-467/. CC BY-SA 4.0. Last updated 2026-10-29.

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Time

Eras, timelines, this day in history, any year in the Islamic world.
Related

Jameh Mosque of Isfahan

Draft card for the Jameh Mosque of Isfahan, the great congregational mosque that grew across centuries from the Buyid to the Safavid eras, named from an open reference description (Wikidata); its Mujam al-Buldan coverage is not yet read on the page.