Ernst Casimir van Nassau-Dietz was born 22 December 1573 in Dillenburg, Hesse, Germany to Johann VI. von Nassau-Dillenburg (1535-1606) and Elisabeth von Leuchtenberg (1537-1579) and died 2 June 1632 Siege of Roermond of unspecified causes. He married Sophie Hedwig von Braunschweig-Wolfenbüttel (1592-1642) 1 June 1607 in Gröningen, Saxony-Anhalt, Germany.
Ernst Casimir, Count of Nassau-Dietz, Stadtholder of Friesland, Groningen and Drenthe. He fell in the Battle of Roermond.
Children
| Name | Birth | Death | Joined with |
| NN van Nassau-Dietz (1608–1608) | |||
| NN van Nassau-Dietz (1609-1609) | |||
| NN van Nassau-Dietz (1610-1610) | |||
| Hendrik Casimir I van Nassau-Dietz (1612-1640) | 21 January 1612 Arnhem | 13 July 1640 Hulst | |
| Willem Frederik van Nassau-Dietz (1613-1664) | 7 July 1613 Arnhem, Gelderland, Netherlands | 31 October 1664 Leeuwarden, Friesland, Netherlands | Albertine Agnes van Nassau (1634-1696) |
| Elisabeth van Nassau-Dietz (1614-1614) | |||
| Johan Ernst van Nassau-Dietz (1617-1617) | |||
| Maurits van Nassau-Dietz (1619-1628) | |||
| Elisabeth van Nassau-Dietz (1620-1628) | |||
Footnotes (including sources)
| ‡ General |
