Clandestine Christian communities existed in Kiev for decades before the official baptism.
The baptism of Kiev most likely occurred in 988, when the Prince Vladimir I of Rus exhorted the residents of the capital city Kiev to the Dnieper river for baptism. This mass baptism became the iconic inaugural event in the forced Christianization of the state of Kievan Rus'. It was preceded by Vladimir's personal baptism in the city of Korsun, or Chersones, in Crimea.
Legend says that at first Vladimir baptised his 12 sons and many boyars. He destroyed the wooden statues of Slavic pagan gods that stood on the hill by Vladimir's palace (the very same statues that he had himself raised just eight years earlier). They were either burnt or hacked into pieces, and the statue of Perun—the supreme god—was thrown into the Dnieper. Then he sent a message to all residents of Kiev, "rich, and poor, and beggars, and slaves", to come to the river on the following day, lest they risk becoming the "prince's enemies". Large number of people came; some even brought infants with them. They were sent into the water while Christian priests, who came from Korsun for the occasion, prayed.
To commemorate the event, Vladimir built the first stone church of Kievan Rus', called the Church of the Tithes (Desyatynna Tserkva), where his body and the body of his wife, Princess Anna, the sister of Byzantine Emperor Basil II, were to repose. Another church was built on top of the hill where pagan statues stood before.
In 1988, the faithful of the Eastern Orthodox churches which have roots in the baptism of Kiev celebrated a millennium of Eastern Slavic Christianity. The great celebrations in Moscow changed the character of relationship between the Soviet state and the church. For the first time since 1917, numerous churches and monasteries were returned to the Russian Orthodoxy. In Ukrainian communities around the world, members of various Ukrainian churches also celebrated the Millenium of Eastern Slavic Christianity.
- Oleg M. Rapov, Russkaya tserkov v IX–pervoy treti XII veka (The Russian Church from the 9th to the First 3rd of the 12th Century). Moscow, 1988. – particularly valuable for the learned discussion of the baptism's date.