Saint Vladimir, also known as Vladimir the Great, was a ruler of Kievan Rus' from 980 to 1015. He is best known for Christianizing the region, which significantly influenced the culture and development of Eastern Europe. His conversion to Christianity in 988 marked a pivotal moment in the history of the region, leading to the establishment of the Eastern Orthodox Church in Russia. Vladimir is often depicted holding a cross and is recognized as a saint in both the Eastern Orthodox Church and the Roman Catholic Church. His feast day is celebrated on July 15 in the Orthodox tradition. He is remembered for his efforts to unify the diverse tribes of Kievan Rus' and promote a common faith and culture.