Slavs are customarily divided along geographical lines into three major subgroups: West Slavs, East Slavs, and South Slavs, each with a different and a diverse background based on unique history, religion and culture of particular Slavic groups within them. Apart from prehistorical archaeological cultures, the subgroups have had notable cultural contact with non-Slavic Bronze- and Iron Age civilisations.

Who is customarily divided along geographical lines into tree major subgroups?