Ancient Bear Cult draws its inspiration from prehistoric and early medieval soundscapes. All of the instruments used by the band have a history of hundreds of years, so it is possible that similar bands have existed in the distant past. Since no music has survived from those times, neither as sheet music nor any other form, the members of A.B.C. have composed most of the songs in the band's repertoire by themselves, with the exception of performing also some old European folk tunes.

Instruments used by A.B.C. include Viking lyre, crwth and hurdy gurdy. Viking lyre is a replica of an instrument that was found in a grave of a Viking chief in the island of Gotland and has been dated to ca. 700 A.D. The ancient Welsh instrument crwth closely resembles Viking lyre but is, instead of plucking, played with a bow. Hurdy gurdy was used in medieval Europe for dance accompaniment.