The exact date of birth of the princess is unknown, except that she was the daughter of the mentioned Rogneda, who was married to Vladimir from 978 to 987 . Mstislava is mentioned among the three daughters of Vladimir, taken in concubines by the King of Poland Boleslaw the Brave in 1018.  According to the assumption of the Polish historian Lyabuda, in Poland the captured daughters of Vladimir lived in a palace on the Lednice Island, and they were not forced to accept Catholicism. Around 1025 , when Boleslaw the Brave died, the captives were freed . After that, Mstislava is not mentioned anywhere. She did not have a family.