Mieszko Bolesławowic was facilitated by a deal between Ladislaus I of Hungary and Władysław I Herman. Another version, publicized by a Hungarian chronicler, claims that in 1086 Ladislaus I of Hungary invaded the Kingdom of Poland, took control of Cracow, and installed Mieszko as its ruler. Though there is no direct primary source evidence for this, notes in Cracow almanacs strongly suggest that during the years 1086 - 1089 Mieszko was prince of Cracow. However, sometime during this time he accepted over-lordship of his uncle Wladyslaw I Herman, and gave up his hereditary claim to the crown of Poland in exchange for
Mieszko Kazimierzowic "Gesta principum Polonorum" written in the early 12th century, put Mieszko third in order, among his brother. Modern historian, Janusz Bieniak, has supposed that Mieszko was the second son of Casimir I and was older than Władysław Herman, but most scholars disagree with this hypothesis. The date of Mieszko's birth was given by "Rocznik krakowski" (Kraków Annals). This source omitted dates of birth of Mieszko's brothers. Kazimierz Jasiński thought that "Rocznik" was started shortly before Mieszko's birth and this was the reason for absence of his older brothers. Przemysław Wiszewski supposed tha Casimir I chose Mieszko as his successor and