Mieszko I Tanglefoot the city and was proclaimed the new High Duke of Poland. Mieszko III the Old found himself in exile in Racibórz and it seemed that the war between Mieszko Tanglefoot and Casimir II the Just was now just a matter of time. Casimir II, however, went a different route and, in order to gain the favor of the Duke of Racibórz given him the towns of Oświęcim and Bytom (with the fortress of Oświęcim, Bytom, Mikołów, Siewierz and Pszczyna, although some historians estimate that these fortress had belonged to Mieszko only since 1179). On the other hand, Bolesław the Tall
Mieszko I of Poland copying the document he made a mistake and wrote down Dagome instead of Dagomer or even Dagomir. The name Dagomir is used to this day and its construction is similar to other Polish names like for example: Władimir/Włodzimierz or Casimir/Kazimierz. The evolution of the "-mir" element to "-mierz" is due to two separate developments: first, the regular change of the vowel "i" to "(i)e" before "r", and second, the modification of the nominative case by the vocative for certain names (hence, Kazimierz replaced Kazimier based on the vocative Kazimierze). It is debatable whether the name Mieszko is a nickname formed