 Complete the following phrase:  In 1067, Vseslav rebelled in an attempt to overthrow Izyaslav and become Grand Prince himself, claiming the right as a great-grandson of Vladimir the Great through Izyaslav Vladimirovich. Vseslavs attempt was unsuccessful, and ended in his imprisonment. Troubles for Izyaslav were to continue though. In 1068, Izyaslavs alleged negligence to the advances and incursions of the Cuman people Polovtsy after the defeat at the 