 South Slavic "ban" (, with a long ) possibly comes from the Turkic word "bajan" (rich, wealthy), which entered the Croatian language through the Avars.There are also theories that it is an Illyrian derivative.The long form is directly attested in 10th-century Constantine Porphyrogenitus' book "De Administrando Imperio" as "", in a chapter dedicated to Croats and the organisation of their state, describing how their ban "has under his rule Krbava, Lika and Gacka."