She was a member of the Berkeley family and, according to her Wikipedia article, "was an author, playwright, traveller, and socialite, perhaps best known for her travelogues..." This is not what many people in the USA think of when you mention the word "Berkeley."
Her Wikipedia article continues: "Her life was full of scandal: after thirteen years of marriage, six children, and affairs reported on both sides, she and her first husband, William Craven, 6th Baron Craven, (married since 30 May 1767), parted permanently in 1780. Thereafter she lived in France and travelled extensively on the Continent.
For a number of years she was in a relationship with Alexander, Margrave of Brandenburg-Ansbach and Bayreuth. His wife since 1754, Princess Friederike of Saxe-Coburg-Saalfeld, died in Germany on 18 February 1791, and Lady Craven's husband died in Lausanne on 26 September 1791. The couple married in Lisbon on 30 October 1791. They settled in England and while the Margravine was snubbed by ladies mindful of their reputations, as well as by her latest husband's cousin, George III himself, the couple lived a busy and opulent life in Hammersmith, London and Benham Park at Speen in Berkshire.
Nonetheless, Elizabeth was never legally entitled to share her husband's German rank and title: On 20 February 1801, she was granted the morganatic title of 'Princess (Fürstin) Berkeley' by the last Holy Roman Emperor Francis II. In fact, Christian Frederick, being the last of his cadet branch of the House of Hohenzollern, and childless, had exchanged his hereditary birthright to the appanages of Ansbach and Bayreuth for an annuity of 300,000 guilders from his pater familias, King Frederick William II of Prussia, a month after his second marriage. In England, however, the couple were usually known as the 'Margrave and Margravine of Brandenburg-Ansbach.'..."