Stephanos of Byzantium - Ethnika
Kassope: a city among the Molossoi, which gives its name to the Kassopia region. The ethnonym is 'Kassopaios', also 'Kassopios' and 'Kassopia'. 'Kassopias' is from 'Kassopios', as in 'Helikonias'. Herodoros calls them 'Kassopous', perhaps wrongly. All write it with two σ’s, but Herodian alone with one σ.
Stephanos excerpt (left) is aligned with matched Herodian passages (right). Colors indicate corresponding overlap spans.