Where does “Vjačeslavs” come from?
Vjačeslavs (Latvian) comes from Russian Вячесла́в, from Old Russian Вѧчеславъ, from Proto-Slavic *Vęťeslàvъ, from Proto-Slavic slàva, from Proto-Indo-European ḱlew-, from Proto-Indo-European ḱel- — to cover; to incline.
Ancestry of “Vjačeslavs”, step by step