Eufemia of Masovia (1310-1374) (1310–1374) Parents Maria of Galicia Trojden I, Duke of Masovia Children Anna of Cieszyn Elisabeth of Cieszyn Jan of Cieszyn Bolesław of Cieszyn Agnes of Cieszyn Przemyslaus I Noszak, Duke of Cieszyn Władysław of Cieszyn Jolanta Helena of Cieszyn Siemowit of Cieszyn Siblings Bolesław Jerzy of Mazovia Alexandra of Pomerania Siemowit III, Duke of Masovia Sophie of Pomerania, Duchess of Pomerania Casimir of Masovia Partners Casimir I, Duke of Cieszyn