Piast Dynasty
Further information: History of Poland during the Piast dynastyDuring the Piast dynasty rule (10th–14th century), Poland was formed and established as a state and a nation. The historically recorded Polish state begins with the rule of Mieszko I in the second half of the 10th century. Mieszko chose to be baptized in the Western Latin Rite in 966. Mieszko completed the unification of the West Slavic tribal lands fundamental to the new country's existence. Following its emergence, the Polish nation was led by a series of rulers who converted the population to Christianity, created a strong kingdom and integrated Poland into the European culture.
Mieszko's son Bolesław I Chrobry established a Polish Church province, pursued territorial conquests and was officially crowned in 1025, becoming the first King of Poland. This was followed by a collapse of the monarchy and restoration under Casimir I. Casimir's son Bolesław II the Bold became fatally involved in a conflict with the ecclesiastical authority, and was expelled from the country. After Bolesław III divided the country among his sons, internal fragmentation eroded the initial Piast monarchy structure in the 12th and 13th centuries. One of the regional Piast dukes invited the Teutonic Knights to help him fight the Baltic Prussian pagans, which caused centuries of Poland's warfare with the Knights and then with the German Prussian state. The Kingdom was restored under Władysław I the Elbow-high, strengthened and expanded by his son Casimir III the Great. The western provinces of Silesia and Pomerania were lost after the fragmentation, and Poland began expanding to the east. The consolidation in the 14th century laid the base for, after the reigns of two members of the Angevin dynasty, the new powerful Kingdom of Poland that was to follow.
Read more about this topic: History Of Poland