Jan of Cieszyn Of Noble birth, but led clerical life around Warsaw (1339–1359) Parents Casimir I, Duke of Cieszyn Eufemia of Masovia Children Siblings Siemowit of Cieszyn Przemyslaus I Noszak, Duke of Cieszyn Bolesław of Cieszyn Jolanta Helena of Cieszyn Agnes of Cieszyn Elisabeth of Cieszyn Władysław of Cieszyn Anna of Cieszyn