Yaroslav (Yaroslav the Wise)yərəslävˈ, 978–1054, grand duke of Kiev (1019–54); son of Vladimir I. Designated by his father to rule in Novgorod, he became grand duke of Kiev after defeating his older brother Sviatopolk, who succeeded Vladimir I. A shrewd statesman, he consolidated the power and prestige of Kievan Rus. He regained W Galicia from the Poles (who had obtained it in return for supporting Sviatopolk), crushed (1036) the Pechenegs (nomadic invaders), and suppressed rebellions by Lithuanian and Finnish tribes. In 1043 he organized the last Russian campaign against Constantinople, in which his troops were routed. At home he encouraged learning, codified laws, erected magnificent buildings and churches, including the famous Cathedral of St. Sophia, and founded (1039) a patriarchate in Kiev. Yaroslav was in close contact with European dynasties; his daughters were married to Harold III of Norway, Andrew I of Hungary, and Henry I of France. Before his death Yaroslav divided his kingdom among his heirs, designating the oldest, Iziaslav, as grand duke of Kiev. The others were told to obey Iziaslav as they had their father, but civil war ensued.