The Duchy of Poland was a historical state that emerged in the 10th century, primarily under the rule of the Piast dynasty. It marked the beginning of Polish statehood, with its first notable leader being Mieszko I, who united various Slavic tribes and adopted Christianity in 966 AD, which helped to strengthen the duchy's influence. In 1025, the Duchy of Poland was elevated to a kingdom, becoming the Kingdom of Poland. Throughout its early history, the duchy faced challenges from neighboring powers and internal divisions, but it laid the foundation for the future development of Poland as a significant European nation.