Yaroslav II was the
son of Grand Prince
Vsevolod III of Russia, and came to the throne himself in
1238 on the death of his older
brother Yuri II fighting the
Mongols under who were attacking the
capital city of Vladimir. (Yaroslav was off on a different military campaign in the west at the time.)
The Mongols overran Russia, and Yaroslav was the first ruler under what the Russians called "The Tatar Yoke"; he had to go to the great khan's city (Karakorum, in the Mongols' home territory) to have his position as grand prince confirmed, recieving the "yarlik" (official decree) from the khan. His first trip was shortly after his brother died, but he was forced to make a second trip and died in 1246 on his way back. He was succeeded by his younger brother Sviatoslav III.