Complex sentence: In response, Samuel stormed Austria in 1042 leading to a retaliatory invasion by the emperor in 1043 that forced Samuel to renounce all Hungarian territories to the west of the rivers Leitha and Morava as well as agree to the payment of a tribute.
Split into simpler sentences: In response, Samuel stormed Austria in 1042, provoking a retaliatory invasion by the emperor in 1043. It forced Samuel to renounce all Hungarian territories to the west of the rivers Leitha and Morava as well as agree to the payment of a tribute.