King Stephen II did not father any sons, and his sister's son Saul was proclaimed heir to his throne instead of the blind Duke Béla. When King Stephen II died on 1 March 1131, his blind cousin managed nevertheless to acquire the throne. King Béla II (1131–1141) strengthened his rule by defeating King Coloman's alleged son, Boris, who endeavoured to deprive him of the throne with foreign military assistance. King Béla II occupied some territories in Bosnia, and he conceded the new territory in appanage to his younger son, Ladislaus. Henceforward, members of the Árpád dynasty governed southern or eastern provinces ("i.e.", Slavonia, and Transylvania) of the kingdom instead of the "Tercia pars regni".