The name is believed to derive from the hydronym of the river Bosna that courses through the Bosnian heartland. According to philologist Anton Mayer, the name ''Bosna'' could derive from Illyrian *"Bass-an-as", which in turn could derive from the Proto-Indo-European root "bos" or "bogh", meaning "the running water". According to the English medievalist William Miller, the Slavic settlers in Bosnia "adapted the Latin designation ... Basante, to their own idiom by calling the stream Bosna and themselves ''Bosniaks''".