Oleg of Novgorod
In 882, Rurik's successor, Oleg of Novgorod, conquered Kiev and founded the state of Kievan Rus'. Novgorod's size as well as its political, economic, and cultural influence made it the second most important city in Kievan Rus'. According to a custom, the elder son and heir of the ruling Kievan monarch was sent to rule Novgorod even as a minor. When the ruling monarch had no such son, Novgorod was governed by posadniks, such as the legendary Gostomysl, Dobrynya, Konstantin, and Ostromir.