Kievan Rus from 912-945 was ruled under the Riurikid dynasty by Igor. Olga, a Viking, joined the Riurikid family when she married him. In 942, she gave birth to Igor's son, Sviatoslav. In 945, Igor and his men extorted an unusually large tribute from the Derevlians, a Slavic tribe. Igor decided to return back for more but was ambushed and killed. From this, the Riurikid family's control over Kievan Rus was on the brink of collapse as Sviatoslav was a mere toddler, necessitating that the widow Grand Princess Olga became regent. Olga’s three immediate actions of handling the rebels became known as "Olga's Vengeance". First, after the leader of the Derevlians (Prince Mal) proposed marriage to Olga in hopes to control Sviatoslav, Olga ordered her men to dig a ditch and bury the Derevlian embassy alive. Second, she tricked Prince Mal’s best men into locked bathhouses and burned them alive. Third, Olga held a feast where Derevlians, oblivious to the fate of their embassies, joined her and when they became drunk, Olga’s army slaughtered five thousand of them. The next year she invaded the land of Dereva. Subsequently, Olga requested pigeons and sparrows from each Derevlian household as tribute and attached flaming pieces of paper to the birds’ feet. She released them, causing the city to light aflame, bringing the demise of the Derevlians. Resubjugating the Derevlians was only a partial measure towards securing the Riurikid dyansty. In 954, Olga was baptized by the Patriarch in Constantinophle and converted to an Orthodox Christian. Olga's conversion was bold because she now belonged to a small religious minority among an majority of Kievan Rus paganists. Olga’s reason for conversion was to strengthen Kiev's position to its powerful neighbor, the Byzantine, because Kiev's Slavic neighbors had already adopted Christianity as their official religion. As a pagan holdout, Kiev found itself isolated from the diplomatic circles of Christian Europe. With administrative reforms, Olga established a permanent royal presence through the installation of appointed officials, formalization of tax collection and the minting of coins. Since the tax items were bound for markets in Constantinople, Kiev must maintain positive relations with the Byzantine. Olga also understood the potential threat to Kievan autonomy, as evidenced by her refusal of the Byzantine Emperor's proposal of marriage. In this way Olga averted Byzantine conquest of Kiev.
Olga’s biography was accounted in The Tale of Bygone Years by two Christian monks. Her account was most likely over exaggerated because the authors wanted to demonstrate the stark moral makeover brought on by Olga’s conversion to Christianity. With the description of the pagan Olga's brutality, the monk authors thus demonstrated the miraculous transformative powers of conversion. Much as Buddhist writers attributed brutal acts of oppression to the Indian Emperor Ashoka, prior to his conversion and subsequent valorization of non-violence.