James Boswell's uncle John was a member of a sect known as the Glasites.
Lodewijk Theodoor II van Nassau-LaLecq
Lodewijk Theodoor II van Nassau-LaLecqBorn 1741
Son of Lodewijk Theodoor I van Nassau-LaLecq (1701-1748) and Josina Geertruida Crommelin (1715-1756). Married firstly (1767) to Jeanne Françoise Elisabeth de Crousaz (1745-1768). Married secondly (1768) to Anne Pauline Marie de Chandieu-Villars (1744-?).
Lodewijk Theodoor was adopted by his uncle, Hendrik Karel, in 1752. He inherited the title of Ourwerkerk from his Uncle William Hendrik in 1762, but sold it to another uncle Jan Nicolaas Floris in 1773. Editor (1779-1784) of De Staatsman, a political magazine. He converted to Catholicism in 1786.
A Count d'Ouwerkerke was mentioned by Boswell on November 26, 1763, when Boswell met him at the Countess of Nassau Beverweerd's. He wasn't identified for certain at the time of publishing of Boswell in Holland, but there seems little doubt that Lodewijk Theodoor II is the person Boswell referred to, i.e. he was adopted by the Count of Nassau Beverweerd, where Boswell met him, and was styled Heer van Ouwerkerk from 1762 to 1773.
Boswell described him as "lively, good-humoured, and quite a little man of the world." Later on, in conversation with the Count's sister, he told her that "Your brother was my good friend. He taught me all the etiquette. He is always gay. He speaks French well. He speaks very fast". (December 21, 1763)