Maria of Ostfriesland (1582-1616) (1582–1616) Parents Catherine Vasa of Sweden Edzard II, Count of East Frisia Children Siegmund Hienrich von Braunschweig-Lüneburg-Dannenberg Marie Katharina of Brunswick-Dannenberg Siblings Anne of Ostfriesland Enno III, Count of East Frisia Christoph Gretsil John III of Rietberg Partners Julius Ernst, Duke of Brunswick-Dannenberg