Bolesław I the Brave in 1025 he had himself crowned King of Poland. He was the first Polish ruler to receive the title of "rex" (Latin: "king"). He was an able administrator who established the "Prince's Law" and built many forts, churches, monasteries and bridges. He introduced the first Polish monetary unit, the "grzywna", divided into 240 "denarii", and minted his own coinage. Bolesław I is widely considered one of Poland's most capable and accomplished Piast rulers. Bolesław was born in 966 or 967, the first child of Mieszko I of Poland and his wife, the Bohemian princess Dobrawa. His "Epitaph", which was written
Mieszko the Younger point, Mieszko III decided to give the district of Kalisz to his youngest son and namesake, as his own Duchy. Mieszko the Younger died on 2 August 1193. He was buried in the crypt founded by his father in the Cathedral of St. Paul the Apostle in Kalisz. Tombstones of Mieszko the Younger and Mieszko III were found during archaeological excavations during 1958–1960. For unknown reasons, Mieszko never married or had children. On his death, Mieszko III give Kalisz to his eldest son Odon. Mieszko the Younger Mieszko the Younger (also known as of Kalisz) () (between 1160 and 1165