Olga of KievKiev, Ukraine
Olga was a regent of Kievan Rus' for her son Sviatoslav from 945 until 960. Following her baptism, Olga took the name Elenа. She is known for her subjugation of the Drevlians, a tribe that had killed her husband Igor of Kiev. Even though it would be her grandson Vladimir that would convert the entire nation to Christianity, because of her efforts to spread Christianity through Rus', Olga is venerated as a saint in the Eastern Orthodox Church with the epithet "Equal to the Apostles" and her feast day is 11 July.
She was the first woman to rule Kievan Rus'. Little is known about Olga's tenure as ruler of Kiev, but the Primary Chronicle does give an account of her accession to the throne and her bloody revenge on the Drevlians for the murder of her husband as well as some insight into her role as civil leader of the Kievan people.