@rasmusfleischer indeed there's two distict cossack groups right in the area north of Circassia, one are Circassian Christians (who considered themselves Ruskiye) and in Kuban the displaced Ukrainain cossacks from dismantled Sich (done by Katharina II's decree). Those at Don would kidnap Circassian women and dress like Adyges so no suprise they'd even call themselves Circassians. The 'Ruskoy' part would be faith, and language too