Background
He was the fifth son of Casimir I, Duke of Cieszyn, by his wife Euphemia, daughter of Duke Trojden I of Czersk-Warsaw.
He was the fifth son of Casimir I, Duke of Cieszyn, by his wife Euphemia, daughter of Duke Trojden I of Czersk-Warsaw.
As a Teutonic Knight, Siemowit was successively named komturem of Oleśnica Mała near Oława since 1360, Prior of Poland, Bohemia, Moravia, Austria, Styria and Carinthia since 1372 and Governor and Treasurer of the Order in Germany since 1384. Siemowit"s place of burial is unknown.