Mieszko I of Poland Mieszko I of Poland Mieszko I (; – 25 May 992) was the ruler of the Polans from about 960 until his death. A member of the Piast dynasty, he was a son of the legendary Siemomysł, and a grandson of Lestek. He was the father of Bolesław I the Brave (the first crowned king of Poland) and of Gunhild of Wenden. Most sources make Mieszko I the father of Sigrid the Haughty, a Nordic queen, though one source identifies her father as Skoglar Toste, and the grandfather of Canute the Great (Gundhild's son), and the great-grandfather of Gunhilda of
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