Geography of Poland today's modern Polish society. The ancestors of today's Poles, the Polanie, built their first fortresses on islands in these lakes. The legendary Prince Popiel ruled from Kruszwica tower erected on the Lake Gopło. The first historically documented ruler of Poland, Duke Mieszko I, had his palace on an island in the Warta River in Poznań. Nowadays the Polish lakes provide a location for the pursuit of water sports such as yachting and wind-surfing. The Polish Baltic coast is approximately long and extends from Świnoujście on the islands of Usedom and Wolin in the west to Krynica Morska on the Vistula
Mieszko I, Duke of Cieszyn the church. Thanks to him, the construction was completed of the Dominican convent at Oświęcim (shortly after 1283). Also, he financially assisted the monastery of Czarnowąsy near Opole and in the Dominican of Cieszyn. Mieszko's exact date of death is unknown. Diplomatic sources suggest that he died in 1314 or in the first half of 1315, before 27 June. He was probably buried in the Dominican church in Cieszyn. In 1931 the Polish painter and sculptor Jan Raszka made a sculpture of Mieszko I in Cieszyn. According to some sources, Mieszko's wife died around 1303, but her name is unknown.