Short answers, pulled from the story.
Vladimir the Great was baptized in 988 at the town of Chersonesus in Crimea, taking the Christian name Basil. The conversion was tied to a military alliance with Byzantine emperor Basil II and to Vladimir's marriage to the emperor's sister, Anna.
Vladimir the Great was a follower of Slavic paganism before 988. He built a pagan temple on a hill in Kiev dedicated to six gods, including Perun, Stribog, Dazhd'bog, Mokosh, Khors, and Simargl, and he kept hundreds of concubines.
Vladimir fled Novgorod in 977 after his brother Yaropolk killed their brother Oleg to become sole ruler of Rus'. He assembled a Varangian army abroad, returned in 978, captured Polotsk and Smolensk on his way south, and took Kiev by killing Yaropolk through treachery.
Vladimir the Great was canonized by the Eastern Orthodox Church, the Byzantine Rite Lutheran Church, and the Roman Catholic Church for Christianizing the Kievan Rus' after his baptism in 988. His feast day is celebrated on the 15th and the 28th of July.
Vladimir the Great introduced the Byzantine law code into his territories but reformed its harsher provisions. He abolished capital punishment, judicial torture, and mutilation. He also established ecclesiastical courts and ordered the education of noble children.
Vladimir the Great was born around 958 to Sviatoslav I of Kiev and Malusha, a housekeeper. Malusha was described in Norse sagas as a prophetess. Vladimir was the illegitimate and youngest son of Sviatoslav I.