Malik Shah I

Malik Shah I's forces, commanded by his general Alp Arslan, defeated the Byzantine army at Manzikert in eastern Anatolia. Emperor Romanos IV Diogenes was captured, leading to a Byzantine civil war and opening Anatolia to Turkish settlement.

Under Malik Shah I and his vizier Nizam al-Mulk, the Seljuk Empire implemented a centralized administrative system. This included the establishment of the iqta' land-grant system, a standardized tax code, and the construction of caravanserais to promote trade.

Malik Shah I commissioned the expansion and renovation of the Great Mosque of Isfahan (Jameh Mosque). This project added four iwans and a large dome, transforming the mosque into a masterpiece of Persian-Islamic architecture and a model for later mosques.

Vizier Nizam al-Mulk was assassinated by a member of the Assassins (Nizari Ismailis) near Nahavand. His death removed a key stabilizing figure from the Seljuk court and contributed to the subsequent decline of the empire under Malik Shah's successors.

Malik Shah I died in Baghdad shortly after Nizam al-Mulk's assassination, possibly poisoned. His death triggered a succession crisis among his sons, leading to a period of civil war and fragmentation of the Seljuk Empire.