Daughter of Willem Hendrik van Nassau La-Lecq (d. 1762), and Adriana Jacoba Noiret (1699-1724). Married (1749) to Alexander Sweder.
Boswell visited Baron and Madame Spaen at the Hague on December 20, 1763. He recorded a part of their dinner conversation, available in [BIH]. Boswell corresponded with her regularly until 1773.