Catherina Belgica of Nassau was born in Antwerp on 3 July 1578 as the third daughter of William of Orange and Charlotte of Bourbon. She was named after her aunt, Catharina of Nassau, who was also her godmother.
She was just four years old when her mother died, and her father was assassinated when she was six. She was taken in by her aunt, as opposed to three of her other sisters, who were taken in by their stepmother Louise de Coligny. She was raised as a Lutheran which was criticised by her elder Louise Juliana, who was a Calvinist. Louise Juliana even wrote to their uncle John how much she was saddened by her sister’s Lutheran education.
Catharina married her cousin, Philip Louis II, Count of Hanau-Münzenberg on 23 October 1596 at Leeuwarden. She received a gift of 20,000 guilders from the States-General. She settled with her husband in Hanau near Frankfurt. They would go on to have ten children, though not all would live to adulthood.
The court at Hanau became a refuge for Protestants, like her sister Elisabeth, Duchess of Bouillon and her husband. They even built a completely new city for the Huguenots, Neustadt-Hanau.
When her husband died in 1612, Catharina acted as regent for her eldest son as he was still a minor. She famously closed the city gates on Emperor Leopold II who was on his way to Frankfurt to be crowned. Four years later the city was overrun by Imperial soldiers, and Catharina and her children fled to The Hague. They would not return for another nine years. She died in The Hague on 12 April 1648 and was the only one of William’s daughters to be interred in the crypt in Delft. [ref]
Jacqueline Doorn, De prijs van het bloed 1584-1625. De kinderen van Willem van Oranje, hun rol en hun lot
J.C. van der Does, Prinsessen uit het huis van Oranje (Putten 1938) 88 – 96 [/ref]