The Idrisid dynasty or Idrisids were an Arab Muslim dynasty from 788 to 974, ruling most of present-day Morocco and parts of present-day western Algeria. Named after the founder, Idris I, the Idrisids were an Alid dynasty descended from Muhammad through his grandson Hasan. Their reign played an important role in the early Islamization of Morocco and also presided over an increase in Arab immigration and Arabization in major urban centers.