Mieszko I, Duke of Cieszyn disappeared. Is unknown why this happened, because at that time he was only around fifty-years-old and was still considered young enough. The government of the Duchy was increasingly absorbed by his sons Wladyslaw and Kazimierz. The only sign of his political activities during this time was the lease of the Czech city of Kęty to the Bishop of Kraków, Jan Muskata, a strong opposer to the rule of Władysław I the Elbow-high in Greater Poland. However, in contrast to his brother Bolko I, Mieszko didn't support the Rebellion of wójt Albert in 1311. Mieszko was known for his generosity to
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