Stephanos of Byzantium - Ethnika
Kassope: a city among the Molossians, eponymous of the region Kassopia. The ethnonym is 'Kassopaios' and 'Kassopios' and 'Kassopia'. From 'Kassopios', 'Kassopias'. But Herodoros says they are 'Kassopous', perhaps incorrectly. All write it with double σσ, but Herodian alone with single σ.
Stephanos excerpt (left) is aligned with matched Herodian passages (right). Colors indicate corresponding overlap spans.