Finally, when Soběslav fell out with his elder brother Duke Vladislaus I of Bohemia in 1123, Conrad II was able to succeed his father in Znojmo. However, Duke Vladislaus died two years later and as the dynastic struggles culminated in the 1126 Battle of Chlumec, Soběslav had Conrad II deposed and imprisoned at Dohna Castle in 1128. In an attempt to reconcile with his Moravian cousin and to stabilise his rule in the Bohemian lands, Duke Soběslav reinstalled Conrad as Znojmo prince and also arranged his marriage with the Vukanović princess Mary (d. 1189), a daughter of Grand Prince Uroš I of Serbia.