Casimir II the Just

Casimir II the Just (1138–1194), a posthumous son of Bolesław III Wrymouth, received no land in his father's testament. In 1157 he was sent to Germany as a hostage for his brother's loyalty to Emperor Frederick Barbarossa.

He ruled Sandomierz from 1173, and in 1177, backed by nobles against his brother Mieszko III the Old, seized Kraków and became high duke of Poland. In 1184 he did homage to Emperor Frederick Barbarossa, and in 1186 inherited Masovia from his nephew Leszek, founding the Masovian Piast line. He ruled Kraków until his death in 1194, though Mieszko briefly displaced him; the Just is a 16th-century title.