 Lothair ruled the Nordmark from 983 to 1003.Bishop Thietmar of Merseburg, Lothair's nephew, tells in his chronicle that Dedo I was involved in the devastation of the castle of Wolmirstedt which was in the possession of the Counts of Walbeck.Dedo's dispute with the House of Walbeck continued with Lothair's son and successor Werner von Walbeck (1003–1009; died 1014).