The woreda is named after a former confederation of the Agew, which James Bruce describes was formed of Dengui, Sakala, Dengila and Geesh.
By the 13th century the following major districts had developed in Estonia: Saaremaa (Osilia), Läänemaa (Rotalia or Maritima), Harjumaa (Harria), Rävala (Revalia), Virumaa (Vironia), Järvamaa (Jervia), Sakala (Saccala), and Ugandi (Ugaunia).