Gąsawa massacre
The Gąsawa massacre (Polish: Zbrodnia gąsawska, lit. 'Gąsawa crime') was an attack on the night of 23 / 24 November 1227 during a council of Polish Piast dukes which was being held near the village of Gąsawa in Kuyavia, Poland. The High Duke of Poland, Leszek the White, was assassinated, and Duke Henry the Bearded of Silesia was gravely wounded.
At the time of the attack some of the victims were bathing in preparation for retiring for the night, and so the event is also known in Polish historiography as the Gąsawa bloodbath (Polish: krwawa łaźnia w Gąsawie).