In the X — XI centuries, almost all Eastern Slavic unions of the tribes were united within the framework of Kievan Rus. The most famous feudal state formations in this period in the modern Belarus territory are the Polotsk, Turovo-Pinsk and Gorodensk princedoms.
The Polotsk princedom periodically fell under the authority of Kiev, but soon it became in fact an independent state with all the relevant attributes – the sovereign power of the prince, the administration, the capital, the army, and the fiscal system. The Polotsk principality expanded its influence in the Baltic States, subjugating a number of Baltic tribes. In X — XII centuries, the Polotsk principality covered a vast territory, including the north and the center of modern Belarus, as well as part of the lands of modern Latvia, Lithuania and the Smolensk region of Russia.
The question of the legality of considering the Polotsk principality as part of Kievan Rus is disputed by a number of Belarusian historians. It is considered that the first centers of consolidation of the East Slavic tribal unions, where princely dynasties were born, were not only Kiev and Novgorod, but also Polotsk.
By the middle of the X century, the Polotsk principality was ruled by Prince Rogvolod, who had no relation to the Rurik dynasty. Around 980, Rogvolod, along with his two sons, was killed by Prince Vladimir, while his daughter, Rogneda, was forced to marry him by force. Vladimir had three sons born of Rogneda: Izyaslav (circa 978-1011), Yaroslav (c. 978-1054) and Vsevolod (983/984 – until 1013).
Gradually, new cities appeared – Volkovysk (first mentioned in 1005), Brest (1019), Minsk ( 1067 ), Orsha ( 1067 ), Logoisk (1078), Pinsk (1097), Borisov (1102), Slutsk (1116), Grodno ( 1128), Gomel (1142). Cities were becoming political, economic and cultural centers.
At the end of the 10th century, with the baptism of Russia in the Eastern Slavic principalities on the territory of modern Belarus, writing based on the Cyrillic alphabet began to spread.
Under Vseslav Bryachislavich, the Principality of Polotsk reached the peak of its power. However, after his death began the decline of the principality.
After the disintegration of Kievan Rus, the Polotsk principality actually became independent, but very soon it split into separate principalities.