Leszek I the White
The most important duke was Swiętopełk II who in Kashubian traditional history carries the nickname "the Great". Swiętopełk received Pomerelia as vassaldom from his suzerain, the Polish High Duke Leszek I the White of the Piast dynasty in 1216 or 1217. Perhaps acting in concert with the Piast prince Władysław Odonic of Greater Poland he benefited from his ally action when they had High Duke Leszek I and Duke Henry I the Bearded of Silesia kidnapped and then Leszek murdered during the Gąsawa Piast assembly in 1227. As a result, Swiętopełk declared himself an independent ruler and "dux" of Pomerania.