The Duchy of Sandomierz (Latin: Ducatus Sandomirensis, Polish: Ksiestwo sandomierskie) was one of the territories created during the period of the fragmentation of Poland (early 12th century). It was originally part of the central Seniorate Province, inherited by Duke Henry of Sandomierz (see Testament of Boleslaw III Krzywousty). The Duchy was located in southeastern corner of the Kingdom of Poland, between the rivers of Pilica, Vistula, San, and Dunajec. Since late Middle Ages, it became part of historic province of Lesser Poland, together with adjacent Duchy of Kraków. In the early 14th century, the Duchy was turned into Sandomierz Voivodeship. Its main urban centers were historic towns of Sandomierz and Wislica. Other main towns were Lublin, Radom, Checiny, Pilzno, Luków and Stezyca.