Casimir III of Poland, also known as Casimir the Great, ruled from 1333 to 1370. He was the last king of the Piast dynasty and is known for his efforts to strengthen the Polish state. Casimir implemented various reforms, including legal and economic changes, which helped improve the country's infrastructure and promote trade. Under his reign, Casimir expanded Poland's territory and established important alliances. He is credited with founding several cities and universities, including Kraków, which became a cultural center. His legacy includes the promotion of Polish law and the establishment of a more centralized government.