Where does “slavernij” come from?

slavernij (Dutch) comes from Dutch Slaaf, from Middle Dutch slave, from Late Latin Sclavus, from Byzantine Greek Σκλάβος, from Proto-Slavic slověninъ, from Proto-Slavic slovo, from Proto-Balto-Slavic ślawas, from Proto-Indo-European ḱléwos — to cover; to incline.

slavernij (Dutch): slavery; oppression, submission, bondage