APersonIndependent states
Malik-Shah I
Great Seljuk sultan (1072-1092): ruler of the empire at its widest and most peaceful, who adopted Omar Khayyam's calendar.
Malik-Shah was Alp Arslan's son and came to the throne at seventeen when his father was killed in 1072. He governed with the help of his vizier Nizam al-Mulk; in this period the Seljuk empire stretched from Kashgar and Transoxiana to Syria and Anatolia.
In his reign the Nizamiyya madrasas were founded and the Friday Mosque of Isfahan was enlarged. At Malik-Shah's order Omar Khayyam and other astronomers drew up an accurate solar calendar, called the Jalali calendar after his title. He died in Baghdad in 1092, and after his death the empire was divided among his sons.
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Updated: November 12, 2026