Saint Olga was the wife of Igor, the Prince of Kiev, in the tenth century. When her husband died, she assumed the throne. This was during the evangelization of the Slavic peoples, and Olga herself converted to Christ, and was baptized in Constantinople. She returned to Kiev with a number of priests, and for the rest of her life she ruled justly and worked to spread the Christian faith. Her grandson was the great Prince Vladimir, who would carry on her work in converting the Slavs to Christianity.
Saint Olga fell asleep in the year 969. Her feast is celebrated on July 11. She is titled "Equal-to-the-Apostles" in honor of her incredible evangelistic work.