She was born in Germany to where her mother had gone to avoid political troubles in The Netherlands. Soon her mother, Anna of Saxony, went to visit Wilhelm IV of Hessen-Kassel, leaving her children with Maria Pijpelincx, the wife of Jan Rubens. Not only did she take Jan Rubens with her but, during that journey, they slept together and she became pregnant. After this visit, Anna of Saxony went to live with her three children at the castle of Siegen. However, the relationship between Anna and Jan Rubens was reported to both Anna's husband, the Prince of Orange, and her brother-in-law, Count Johann VI of Nassau-Dillenburg. Consequently, Jan Rubens was imprisoned after he had confessed. The three children, Anna, Maurits and Emilia, were then taken to Dillenburg to be brought up with their uncle's children. Later on they were joined by Christine von Dietz, their mother's illegitimate child.

In 1576 Emilia's brother Maurits left to study in Heidelberg. A year and a half later her sister Anna and much older half-sister Maria returned to The Netherlands to be with their father. Maurits returned to Dillenburg shortly afterward but, together with the whole Dillenburg family, then moved to Siegen to avoid the raging plague. At the end of 1577, Maurits then returned to The Netherlands and their father. Meanwhile, after divorcing Anna of Saxony in 1571, the Prince of Orange had married Charlotte de Bourbon in 1575 and by her fathered six more daughters. Shortly after nursing the Prince after a first assassin's attack, Charlotte died in 1582 and the recovered Prince promptly married Louise de Coligny in 1583. This marriage resulted in one more son about six months prior to the Prince being killed by another assassin on 10 July 1584. From then on her brother Maurits was head of the family as their eldest half-brother Philips Willem was a prisoner in Spain. When her sister Anna married their cousin Wilhelm Ludwig of Nassau-Dillenburg, Emilia went to The Netherlands to attend the festivities. After the marriage, Emilia remained with her sister Anna who, however, became ill shortly afterwards. Anna's husband, Wilhelm Ludwig, also had troubles with his left leg wounded in battle. Wilhelm Ludwig recovered but Anna miscarried on 18 March 1588. She again became pregnant but died in June 1588, so Emilia then went to live in Delft. On 7 February 1595 Emilia was present at the wedding of her half-sister, Maria, who against Maurits's advice, married Count Philipp zu Hohenlohe-Neuenstein. Nevertheless, Maurits was present as so was their youngest half-brother, Frederik Hendrik. After this marriage she went to live in The Hague with her brother Maurits and, being able to converse in French, Latin and Greek, acted as his hostess. As well, she also saw a great deal of Louise de Coligny, her father's widow. At the same time, Emilia had her lady-in-waiting, Margaretha van Mechelen, become Maurits's mistress. However, as Maurits's hostess she met many foreign visitors and amongst these were the Portugese princes, Emanuel and Christoffel. Emilia wrote to Maurits asking permission to marry Prince Emanuel. When Maurits did not reply, they married secretly on 7 November 1597 in a Roman Catholic ceremony. However, the Dutch Government and Maurits not only objected but separated them. Due to all this pressure, Emilia became ill and for a while her condition deteriorated. When she did manage to recover, she was ordered by Maurits to leave The Hague and return to Delft. However, when it became obvious that Emilia still regarded herself as married to Don Emanuel, both Portugese princes were ordered to leave The Netherlands, which they did on 9 December 1597 from Schiedam via Utrecht to Germany. On 12 December Emilia also left and joined Emanuel in Weser in Germany. Maurits let her go as he did not want to appear a tyrant towards his own sister. In June 1598 they were warned that a Spanish army was moving towards Weser and so they moved to Arnhem. Immediately Don Emanuel wrote to the Dutch Government explaining why they had returned to The Netherlands and, after several months, they were permitted to return to Delft. Between June and September 1598, Emilia gave birth to a girl for whom no name has survived but who, on 30 June 1602, was buried in Delft. In June 1599 their second child, Maria Belgica, was born to be followed on 24 February 1600 by a son, Emanuel. On 26 March 1601 there was another son, Louis Guillaume, followed by five more girls. During this period she was very close to her step-mother, Louise de Coligny, and her brother-in-law, Wilhelm Ludwig of Nassau-Dillenburg. Although it took until 1609 before Maurits and Emilia were reconciled, from then on Emanuel accompanied Maurits on his tours through The Netherlands. In 1609 Emilia and Emanuel became the owners of the ruin of the castle of Wychen which they rebuilt. In 1617 they also bought a house in The Hague. During these years Emanuel kept offering his services to the Dutch Government, but each time the Government delayed answering before declining. On 23 April 1625 Emilia was present when her brother, Maurits, died in The Hague. Her grief was such that when the prince's eyes were closed by a recently new sister-in-law, Amalia of Solms, Emilia fainted. The time in The Netherlands was disappointing for Emanuel as all his offers to the Government were declined. Many people had suggested that Emanuel accompany a journey to Brazil as he was popular with the Portugese living there. However, as he was again ignored, he finalized his dealings with the King of Spain and relinquished his rights to the Portugese crown. When he then promised to live in Brussels, Emilia refused to live in any territory belonging to her father's murderer. In June 1626 Emilia with her daughters went to live in Geneva, hoping Emanuel would follow but, together with their son also named Emanuel, he went to the Spanish Netherlands (now Belgium) where they were employed by the Infanta Isabella. Meanwhile Emilia not only became popular in Geneva but was befriended by the local dignatories, including Th‚odore Agrippa d'Aubign‚. Late in 1628 she became ill and died several months later, 16 March 1629. On 3 April 1630, Emanuel married Donna Luisa de Osorio. He died on 22 June 1638 in Brussels. 
 

Source: Leo van de Pas