Casimir I the Restorer not supported by modern historians. Regardless, he left church work for good in 1031. Casimir's father, Mieszko II, was crowned King of Poland in 1025 after the death of his father Bolesław I the Brave. However, the powerful magnates of the country feared a strong central government like the one that existed under Bolesław I's rule. This led to considerable friction between the King and the nobility. Taking advantage of the King's precarious situation, Mieszko II's older half-brother Bezprym and younger brother Otto turned against him and allied themselves with the Holy Roman Emperor Conrad II, whose forces attacked Poland
Mieszko I of Poland from the second part of the name *Dago-mierz, since the merger in pronunciation of "sz" with the devoiced "rz" which would appear in this position is quite recent. However, some historians believe that the word "Dagome" is a melding of two names: the Roman Catholic "Dago," for "Dagobert" (Mieszko's hypothetical baptismal name), and the Slavic "Me," for "Mieszko." The Latin word "iudex" ("judge") would be used in the meaning of "prince." Another interpretation is that "Dagome iudex" is a corruption of "Ego Mesco dux" ("I, Prince Mieszko"). Mieszko I took over the tribal rule after his father's death ca. 950–960,