He was a son of Konstantin Davidovich, prince of Smolensk. He became
the first appanage prince of the Fominsko-Beryezuiskii udel. This was a small
territory that did not play a major political role. Then the Kozlov udel was
formed out of part of this territory. When the entire Smolensk principality
fell to the Lithuanians in the 15th century this udel likewise became extinct.
Yuri's sons were Yuri and Konstantin, princes of
Fominsko-Beryezuiskii udel. We have some names of individuals through five more
generations. They are shown on this family chart.