After the death of Yaroslav the Wise in 1054, a protracted battle for the succession embroiled and, ultimately, partitioned Kievan Rus. Vseslav the Sorcerer, the pagan prince of Polotsk, seized and burned Novgorod and, after Yaroslav’s three sons were defeated in battle by the Turkic Cumans in 1068, he seized Kiev itself, briefly claiming kingship of Rus. Kievan Rus would again achieve some semblance of unity under Vladimir II Monomakh (1113–25) and his son, Mstislav the Great (1125–32) but, by then, other factors were precipitating its decline. The establishment of the crusader kingdom of Jerusalem had opened alternative trade routes to those afforded by Rus; this was accentuated by Constantinople’s decline following its sacking by crusaders in 1204. The growing Cuman Empire, based around the Black Sea, impeded the trade of Rus itself, while Volga Bulgaria controlled the route to the Caspian.