Where does “Святослав” come from?

Святослав (Russian) comes from Old East Slavic Свѧтославъ, from Old East Slavic свѧтъ, from Proto-Slavic svętъ, from Proto-Balto-Slavic śwentas, from Proto-Indo-European ḱwen- — holy, sacred.

Ancestry of “Святослав”, step by step

StepLanguageWordMeaning
1Old East SlavicСвѧтославъSvyatoslav
2Old East Slavicсвѧтъholy, sacred
3Proto-Slavicsvętъholy, sacred
4Proto-Balto-Slavicśwentasholy, sacred
5Proto-Indo-Europeanḱwen-holy, sacred
Every word from Proto-Indo-European ḱwen-Every word from Proto-Balto-Slavic śwentasEvery word from Proto-Slavic svętъ