The Buyid dynasty was a Shia Muslim dynasty that ruled parts of Persia and the surrounding regions from the 10th to the 11th centuries. Founded by the Buyid brothers, it emerged during a time of political fragmentation in the Islamic world, taking advantage of the weakening Abbasid Caliphate to establish their own power. The Buyids are known for their contributions to Persian culture and administration, promoting the use of the Persian language and arts. They played a significant role in the development of Isfahan and Baghdad, where they held significant influence, often acting as de facto rulers while the Abbasids retained nominal authority.