Emilia was born in Cologne. She is named after Amalia of Neuenahr who was in charge of her mother's household at the time of her birth. Emilia's mother had an affair with the father of painter Peter Paul Rubens. Due to this infidelity Emilia and her siblings, Anna and Maurice, were taken out of their mother's care and went to live with their uncle John VI, Count of Nassau-Dillenburg at Dillenburg. Emilia later went to live in Delft with her father and, in Friesland, with her sister, Anna.
Emilia of Nassau
After her father's death she acted as hostess at the court of her brother, Maurice. It was on one of those occasions that she met Dom Manuel de Portugal, (son of pretender to the Portuguese throne, António, Prior of Crato). She secretly wed him in 1597. Maurice was firmly opposed to the marriage, because the Nassaus were Calvinists and Dom Manuel was a Catholic. Maurice put Emilia under house arrest; Dom Manuel had to flee to Wesel. When Maurice found he could not convince her to divorce her husband, he banished her from court for ten years. They eventually made peace and she and Dom Manuel were at Maurice's deathbed.
Emilia and her husband had ten children. The last years of their lives, they lived separately when her husband decided — due to financial concerns — to live in Brussels at the court of Isabella of Spain, archenemy of the House of Orange. Emilia went to Geneva with her daughters, where she died three years later, at the age of 59.
Dek, Anders W. E. (1968). "De afstammelingen van Juliana of Stolberg tot aan het jaar van de Vrede van Munster" [The Offspring of Juliana of Stolberg until the Year of the Peace of Münster]. Spiegel der Historie (in Dutch) 3 (7/8).