Henry died in 1166, killed by the Old Prussians. Since he was childless and had no wife, part of his province, with Wislica, was inherited by his youngest brother, Casimir II the Just, while Sandomierz was seized by Bolesław IV the Curly. The province remained divided until 1173, when Casimir II the Just reunited it. Casimir II died in 1194, and the Duchy of Sandomierz was inherited by Leszek I the White, and his younger brother, Konrad I of Masovia. In c. 1200 the brothers divided their properties, with Konrad receiving Mazovia and Kujawy, while Leszek remained in Sandomierz. In 1205, the two brothers united their forces, defeating Roman the Great in the Battle of Zawichost.