Taking advantage of the internal conflicts in the Holy Roman Empire, Ladislaus besieged and captured the fortress of Moson from Solomon in early 1079. However, Henry IV stormed the western regions of Hungary, and secured Solomon's position. The German invasion also prevented Ladislaus from assisting Boleslaus the Bold, who fled to Hungary after his subjects expelled him from Poland. Ladislaus initiated negotiations with Solomon, who abdicated in 1080 or 1081 in exchange for "revenues sufficient to bear the expenses of a king". However, Solomon soon began conspiring against Ladislaus, and Ladislaus imprisoned him.