Juliane of Salm was the youngest daughter of Johann (1582-1630), Wild- und Rheingraf in Grumbach und Rheingrafenstein and Countess Anna Juliane von Mansfeld (1591-±1626), thus Juliane had been an orphan since around the age of 14.
Juliane married Count Palatine George Wilhelm on 30-11-1641 in his castle in Birkenfeld. He was 25 years her senior. Juliane gave birth within 2½ months of the wedding ceremony on 14-2-1642. The child had been fathered by Count Johann Ludwig of Salm-Dhaun (1620-1673) who belonged to another branche of the same family. On 30-10-1643, however, Johan Ludwig married another relative instead, Elisabeth of Salm-Neuviller (1620-1653).
The family tree below shows how Johan Ludwig was related to both his mistress Juliana and his wife Elisabeth:
| Philipp Franz
Georg Wilhelm (to the right) was Count Palatine of Zweibrücken-Birkenfeld. His first wife, Dorothea of Solms (1586-1625), had died shortly after giving birth to their sixth child. After George Wilhelm married and divorced Juliane of Salm, he was married in 1648 to Countess Elisabeth Anna of Oettingen (1603-1673), widow of general Gottfried Heinrich zu Pappenheim (1594-1632). His name forms the key part of the Czech, Flemish, Dutch, Scandinavian and German colloquialism "I know my fellow Pappenheims". It is used to imply tongue-in-cheek that someone has, is or will be acting in a way that is completely expected. Also the form of rapier called the pappenheimee is named after him.
Sources: http://genealogy.euweb.cz/salm/salm4.html, A. Thiele: Erzählende Genealogische Stammtafeln zu europäischen Geschichte Band I, Teilband 1, Deutsche Kaiser-, Königs-, Herzogs- und Grafenhäuser I, 3. Auflage, de.wikipedia.org.