The region of Kiev will dominate the state of Kievan Rus' for the next two centuries.

The grand prince of Kiev controls the lands around the city, and his theoretically subordinate relatives ruled in other cities and pay him tribute.

The zenith of the state's power comes during the reigns of Prince Vladimir (r. 978-1015) and Prince Yaroslav (the Wise; r. 1019-54).

Both rulers continue the steady expansion of Kievan Rus' that had begun under Oleg.

To enhance their power, Vladimir marries the sister of the East Roman emperor, and Yaroslav arranges marriages for his sister and three daughters to the kings of Poland, France, Hungary, and Norway.

Vladimir's greatest achievement is the Christianization of Kievan Rus', a process that begins in 988.

He builds the first great edifice of Kievan Rus', the Desyatinnaya Church in Kiev.

Yaroslav promulgates the first East Slavic law code, Rus'ka pravda (Justice of Rus'); builds cathedrals named for St. Sophia in Kiev and Novgorod; patronized local clergy and monasticism; and is said to have founded a school system.

Yaroslav's sons develop Kiev's great Peshcherskiy monastyr' (Monastery of the Caves), which functions in Kievan Rus' as an ecclesiastical academy.