Czersk | Czersk, Masovian Voivodeship | Trojden I | Czersk Operational Group | Operational Group "Czersk" |
By 1321, Casimir I married Euphemia (b. 1310 – d. aft. 11 January 1374), daughter of Duke Trojden I of Czersk-Warsaw.
She was the fourth daughter and youngest child of Casimir I, Duke of Cieszyn, by his wife Euphemia, daughter of Duke Trojden I of Czersk-Warsaw.