Cossaei (Ancient Greek: Κοσσαῖοι) were a warlike tribe inhabiting a mountainous district called Cossaea (Κοσσαία), likely related to the Kassites, on the borders of Susiana to the south, and of Media Magna to the north.
Their land was sterile and unproductive, and they lived the life of robbers.
[2] The Persian kings had never been able to reduce them, but had been in the habit of paying them a tribute, when they moved their court annually from Ecbatana to Babylon, to pass their winter at the latter place.
[3] In character, they seem to have resembled the Bakhtiari tribes, who now roam over the same mountains which they formerly occupied.
Pliny calls them Cussii, and in some places they are apparently confounded with the Cissii.