Catherine Vasa of Sweden Regent of East Frisia; Swedish princess, writer (1539–1610) Parents Margaret Leijonhufvud Gustav I of Sweden Children John III of Rietberg Anne of Ostfriesland Christoph Gretsil Enno III, Count of East Frisia Maria of Ostfriesland Siblings Princess Sophia of Sweden Princess Cecilia of Sweden Eric XIV of Sweden John III of Sweden Princess Elizabeth of Sweden Magnus, Duke of Östergötland Charles IX of Sweden Anna of Sweden Partners Edzard II, Count of East Frisia