What is the Jalali Calendar?

The Jalali reform is famously associated with a group of astronomers including Omar Khayyam and is an important milestone in Persian solar calendrical history.

How the calendar is structured

Solar calendar associated with astronomical reform under the Seljuk period.

Where and why it is used

Region: Persian world. Primary context: Historical study and ancestry of later Persian solar systems.

History and development

The system belongs to the Medieval layer of the archive. Its origin is summarized as 11th century. CalculatorWiser separates historical reconstruction, religious observance, civil use, and modern technical standards so different systems are not treated as though they all work the same way.

Visual reference gallery

Conversion and accuracy notes

Some calendar systems can be converted deterministically with modern algorithms. Others depend on observation, local authority, historical reconstruction, or regional practice. CalculatorWiser marks those distinctions rather than presenting uncertain dates as exact.

Research trail

This entry is part of the research-backed World Calendar Archive. Primary research anchor for this entry: Persian calendar history references.