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 III the Old several foreign policy successes through his daughter's marriages: Elisabeth about 1173 married Duke Soběslav II of Bohemia and through the dynastic arrangement between his daughter Anastasia and the Griffin duke Bogislaw I of Pomerania, Mieszko once again reinforced Polish sovereignty over the Pomeranian duchy. In 1177 Mieszko's first-born son Odon, fearing for his inheritance, rebelled against his father. He was supported by Bishop Gedko of Kraków, his cousin Bolesław the Tall and his uncle Casimir the Just. For Odon, the main reason of his rebellion was the favoritism of Mieszko to the offspring of his second marriage and the attempts