Mieszko I of Poland Abraham ben Jacob. According to him, Mieszko I had fought against the Weltaba tribe, commonly identified with the Veleti. Wichmann the Younger, a Saxon nobleman who was then a leader of a band of Polabian Slavs, defeated Mieszko twice, and around 963 a brother of Mieszko, whose name is unknown, was killed in the fighting. The frontiers at the mouth of the Oder River were also desired by the German margraves. In addition, the Veleti Bohemia, which at that time possessed Silesia and Lesser Poland regions, constituted a danger for the young state of the Polans. The chronicle of Thietmar
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