Mieszko I of Poland the conspiracy against Otto II was documented in only one source, the chronicles of the monastery in Altaich in its entry for the year 974. The Duke of Bavaria was defeated, and Emperor Otto II regained full power. Shortly afterwards, the young emperor waged a retaliatory expedition against Bohemia, in 978 forcing Duke Boleslav into submission. In 977 Mieszko's wife, Dobrawa, died. At first there were no apparent repercussions, as the Polish ruler had maintained his alliance with Bohemia. In 979 Otto II supposedly attacked Poland. Mention of this event can be found in the "Chronicle of the Bishops of
Mieszko I of Poland the normalization of relations with the Holy Roman Empire and Bohemia, Mieszko I returned to his plans of conquest of the more western part of Pomerania. On 21 September 967 the Polish-Bohemian troops prevailed in the decisive battle against the Wolinians led by Wichmann the Younger, which gave Mieszko the control over the mouth of the Odra River. The German margraves had not opposed Mieszko's activities in Pomerania, perhaps even supported them; the death of the rebellious Wichmann, who succumbed to his wounds soon after the battle, may have been in line with their interests. A telling incident took place