Poland 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 Spit in the east. For the most part, Poland has a smooth coastline, which has been shaped by the continual movement of sand by currents and
Mieszko I of Poland which facilitated the development of trade. Amber, fur and salt (extracted in Kuyavia and around Kołobrzeg) were exported to other countries, while cloth, crafts, tools and ornaments were imported. According to Gallus Anonymus, before becoming a Roman Catholic Mieszko had seven pagan wives, whom he was required to relinquish, leaving Dobrawa as his only spouse. Nothing is known of the fates of any possible children from these relationships. In 965, before his baptism, Mieszko married Dobrawa (b. 940/45 – d. 977), daughter of Boleslav I the Cruel, Duke of Bohemia. They had two children: According to one hypothesis there was