The Russian Primary Chronicle under 945 refers to the murder of Kievan Prince Igor by his tributary Drevljans and the revenge performed by his widow, Princess Olga. First, she ordered that the embassy from the Drevljans who arrived in Kiev be buried alive; then her servants set fire to the bathhouse where the Drevljan ‘best men’ washed themselves, so that they were burnt alive; and finally, the princess went to the place where her husband was buried and, during a funeral banquet, ordered the massacre of thousands of Drevljans. Each of the acts is interpreted as a ritual connected with the death of the Kievan prince. The three rituals form three stages of the princely funeral ceremony, which was determined by the idea of tripartite structure of the universe. The mythological picture seems to be spread among the Rus ́ and the Slavs of the ten-century Kiev. The story of Princess Olga ended with the expedition of her army to the Drevljan country in the next year, 946. After the long-time besiege of the Drevljan capital, Iskorosten, the city was burned with the help of incendiary pigeons and sparrows. Investigating the origins of the story of incendiary birds among the medieval mythological and literary narratives, the author supposes that it depicts a purifying ritual in the story of Princess Olga. The four disclosed rituals were converted into the historical episodes during the transition of them from oral tradition to the written narrative of the Primary Chronicle. In the origin of the historical narrative one can find the traces of Indo-European mythology and Scandinavian cultural influence.