The Land of Wieluń (Ziemia wieluńska, Velumensis Terra) was a historic land of the Kingdom of Poland and the Polish–Lithuanian Commonwealth, which for centuries was part of Sieradz Voivodeship, Province of Greater Poland. It was based on the medieval Castellany of Ruda, which was established in the 10th or 11th century. The Castellany of Ruda was first mentioned in the 1136 Bull of Gniezno, and during the period known as Fragmentation of Poland (see Testament of Bolesław III Wrymouth, it was part of the Seniorate Province. In the late 12th century, the Castellany was acquired by Duke Władysław Odonic, and in 1217 it became property of Władysław III Spindleshanks. Later on, it was ruled by the Dukes of Silesia from the Duchy of Opole, and in the second half of the 13th century, returned to Greater Poland. In 1281, the castellany was moved from Ruda to Wieluń, and since then, it has been called the Land of Wieluń.