That 1000AD was “Kievan Rus”. A Viking state in Ukraine with the seat of power in what is currently the Ukrainian capital Kyiv.
It fell to the Mongols ~1240. Then 300 years later a different state around Moscow decided they need a more prestigious name than Muscovy and started calling themselves Russia after the long dead Vikings.
On Russian history compared to Ukraine history, enjoy.
Simple facts about Ukraine: ancient, beautiful... and with savage jealous russian neighbour
https://youtu.be/HS9G1WtECgA