What contributions did yaroslav the wise make to kievan russia?

:  In his foreign policy, Yaroslav relied on the Scandinavian alliance and attempted to weaken the Byzantine influence on Kiev. In 1030 he reconquered from the Poles Red Rus, and concluded an alliance with king Casimir I the Restorer, sealed by the latter's marriage to Yaroslav's sister Maria. In another successful military raid the same year, he founded Yuriev (after St George, or Yury, Yaroslav's patron saint) and forced the surrounding province of Ugaunia to pay annual tribute.

One of many statues of Yaroslav holding the Ruskaya Pravda in his hand. See another image here.In 1043 Yaroslav staged a naval raid against Constantinople led by his son Vladimir and general Vyshata. Although the Rus' navy was defeated, Yaroslav managed to conclude the war with a favourable treaty and prestigious marriage of his son Vsevolod to the emperor's daughter. It has been suggested that the peace was so advantageous because the Kievans had succeeded in taking a key Byzantine possession in Crimea, Chersones.

To defend his state from the Pechenegs and other nomadic tribes threatening it from the south he constructed a line of forts, composed of Yuriev, Boguslav, Kaniv, Korsun, and Pereyaslav. To celebrate his decisive victory over the Pechenegs in 1036 (who thereupon never were a threat to Kiev) he sponsored the construction of the Saint Sophia Cathedral in 1037. Other celebrated monuments of his reign, such as the Golden Gates of Kiev, have since perished.