Who was Vladimir the first?

Vladimir I, also known as Vladimir the Great, was a Grand Prince of Kiev who ruled from 980 to 1015. He is credited with the Christianization of Kievan Rus', adopting Byzantine Christianity as the state religion, which significantly influenced the culture and politics of the region. Vladimir is recognized as a saint in the Eastern Orthodox Church, and his legacy includes the establishment of a unified state and the promotion of literacy and trade. His reign is often considered a pivotal moment in the history of Eastern Europe.