Medieval Poland, from the 10th to the 15th century, was a time of significant development and change. It began with the establishment of the Piast dynasty, which united various tribes under the leadership of Mieszko I. The country adopted Christianity in 966, marking a crucial step in its cultural and political integration with Europe. During this period, Poland experienced territorial expansion and the formation of key cities like Kraków and Gniezno. The Teutonic Knights played a significant role in the region, leading to conflicts and the eventual rise of the Jagiellonian dynasty in the late 14th century, which further strengthened Poland's influence in Europe.