Vladimir I was the successor of Kievan Rus after Sviatoslav in 980 to 1015. He was known as the person who was responsible in declaring Christian to be the official state religion in 9888. During his time, Kievan Rus had a good relationship with the Byzantine. Vladimir got married to Basil II’s sister. He got baptized during this marriage, whereas nullified his former marriages. Then, he ordered his sons to govern cities and towns; and each of them was equipped with their own druzhina to help enforcing Christianity onto the people and to ensure the security of Christian priests.