Mstislav I was the son of Grand Prince
Vladimir II Monomakh of
Kievan
Russia and his first wife Gytha, daughter of
Harold II of
England. When he was around 19 in
1095, the people of
Novgorod chose him to be their prince, replacing his cousin David. He led the Novgorod armies in fights with other members of the royal family, and by
1102 the Novgorodians would not let Vladimir and then-Grand Prince
Sviatopolk II move Mstislav to another city.
Mstislav became Grand Prince on his father's death in 1125, and tried to continue his father's policies, but could not really keep a hold on the various princes who claimed the grand prince's throne and would do anything to gain power for the cities they held. He died in 1132 and was succeeded by his younger brother, Yaropolk II.