Where does “Ῥωσία” come from?

Ῥωσία (Greek) comes from Old East Slavic Русь, from Finnish ruotsi, from Proto-Finnic *roocci, from Old Swedish roþs-, from Old Norse róðr, from Proto-Germanic rōþrą, from Proto-Indo-European h₁reh₁- — to row; to separate; loose, sparse, rare.