Mieszko I of Poland Denmark, Canute the Great's daughter and wife of Henry III, Holy Roman Emperor. The first Christian ruler of territories later called Poland, Mieszko I is considered the creator of the Polish state. He continued the policy of both his father and grandfather, who were rulers of the pagan tribes located in the area of present-day Greater Poland. Through both alliances and the use of military force, Mieszko extended ongoing Polish conquests and early in his reign subjugated Kuyavia and probably Gdańsk Pomerania and Masovia. For most of his reign, Mieszko I was involved in warfare for the control of Western
Mieszko I of Poland been between 922–945; the activity of the Duke in his final years of life puts the date of his birth closer to the latter year. There are three major theories concerning the origin and meaning of Mieszko I's name. The most popular theory, proposed by Jan Długosz, explains that Mieszko is a diminutive of "Mieczysław", a combination of two elements or lexemes: "Miecz" meaning sword and "Sław" meaning famous. Today, this theory is rejected by the majority of Polish historians, who consider the name Mieczysław to have been invented by Długosz to explain the origin of the name Mieszko. Today,