Bryachislav Izyaslavich (Belarusian: Брачыслаў Ізяславіч, Russian: Брячислав Изяславич) (c. 997 – 1044) was the prince of Polotsk between 1001 and 1044. His name, possibly, may have been of something in approximation to Vratislav or Wroclaw. He was son of Izyaslav Vladimirovich. During his reign Polotsk was at war with Kiev and Novgorod. In 1015 he has inherited the city of Lutsk after the death of his grandfather Vladimir I of Kiev.

Bryachislav Izyaslavich was born in Polotsk. Either upon his father's death in 1001 or his minor brother Vseslav's in 1003, he inherited the Principality of Polotsk, himself being a child at this time (his grandparents married about 978). Under his rule, Polotsk attempted to distance itself from Kiev. Tensions were exacerbated by the fact that, under the East Slavic house law, since Izyaslav predeceased his father and never reigned in Kiev, his descendants from the House of Polotsk forfeited their dynastic rights to the Kievan throne being classified as izgoi (outcast). In 1020 Bryachislav managed to sack Novgorod, but on his way back he was confronted by an army of his uncle, Yaroslav the Wise. Bryachislav suffered a defeat during the battle on the Sudoma River and fled, leaving behind his Novgorodian prisoners and loot. Yaroslav chased him down and forced him to sign a peace agreement in 1021, granting him only two cities of Usvyat and Vitebsk. Despite this peace agreement, the hostilities between Bryachislav and Yaroslav continued for years. Eventually he extended the territory of his principality and established the city of Braslaw.

The name of his spouse or consort is unknown and he had at least one son, Vseslav of Polotsk, who was the ancestor of all the following Polotsk princes and the only one of them to rule in Kiev.

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