Olga of Kiev was a 10th-century regent of Kievan Rus' who governed on behalf of her son, Sviatoslav, from 945 to 957. Following the death of her husband, Prince Igor, she famously exacted violent retribution against the Drevlian tribe for his murder. As the first Rurikid ruler to be baptized, she paved the way for her grandson, Vladimir the Great, to establish Christianity as the state religion. She is honored in the Eastern Orthodox tradition as a saint with the title "Equal to the Apostles."