Yury Svyatoslavich or Georgy Svyatoslavovich was the last sovereign ruler of Smolensk and Bryansk (1386-95, 1401-04) whose life was spent in vain attempts to fend off aggression by the Grand Duchy of Lithuania. Wikipedia
The definitive Wikipedia entry for Yury Of Smolensk. Wikipedia is the biggest multilingual free-content encyclopedia on the Internet. en.wikipedia.org/wiki/Yury_of_Smolensk