Biography
Johann III. von Ostfriesland, Graf von Rietberg, was born 1566 in Aurich, Lower Saxony, Germany to Edzard II. von Ostfriesland (1532-1599) and Katarina of Sweden (1539-1610) and died 29 September 1625 Rietberg, North Rhine-Westphalia, Germany of unspecified causes. He married Sabina Catharina von Ostfriesland (1582-1618) 4 March 1601 .
Children
| Name | Birth | Death | Joined with |
| Edzard von Rietberg (1602-1603) | |||
| Anna Walburgis von Rietberg (1603-1604) | |||
| Catharina Maria von Rietberg (1604) | |||
| Ernst Christoph von Rietberg (1606-1640) | |||
| Enno Philipp von Rietberg (1608-1636) | |||
| Leopold von Rietberg (1609-1635) | |||
| Walburgis Maria von Rietberg (1612-1613) | |||
| Ferdinand Franz von Rietberg (1613-1648) | |||
| Clara Sophia von Rietberg (1615) | |||
| Anna Clara von Rietberg (1616) | |||
| Johann IV. von Rietberg (1618-1660) | |||
Footnotes (including sources)
| ‡ General |