The Margrave of Brandenburg-Ansbach and Bayreuth succeeded his brother in 1757 at the age of twenty-one. He had married Caroline Friederike of Saxe-Coburg-Saalfeld (1735-1791) in 1754 but had a number of mistresses including the estranged Lady Craven whom he had met in France following her separation from her husband in 1783. Lady Craven, the daughter of the Earl of Berkeley, had a scandalous reputation which her similarly unfaithful husband accepted until their parting in 1783. Their separation was one of the great causes célèbres of 18th century society. Lord Craven had appeared in 1780 with a Mrs. Coxe as 'Lord C... and Mrs. Coxe' in the notorious 'tête-à-tête' portraits in Town and Country Magazine, but it was the amorous escapades of his wife that stole the limelight. The Margrave sold his principality to the King of Prussia in 1791 and married his mistress in October of the same year after the timely death of the Margravine in February and Lord Craven in September.
The Margrave and his new Margravine took up residence in England, where they lived in state at Brandenburg House in Hammersmith. Lady Craven was well-known in society as the Margravine of Ansbach and was the author of numerous plays as well as A Journey through the Crimea to Constantinople. She is often mentioned by Horace Walpole, who admired her beauty, talents and her perfect frankness. Serena Holroyd wrote from Bath on November 23, 1791, "I was told that Lady Craven, on hearing of her Lord's [Lord Craven's] death, put on deep mourning that very day, wept, and went through the whole ceremony of a widow. The next morning she wiped her tears, threw off her weeds, put on bridal trappings and was married to the Margrave!".
The Margravine published her memoirs in 1826. These were republished in 1914 by A.M. Broadley and L. Melville, The Beautiful Lady Craven in two volumes and both the lengthy introduction and the text itself extols the richness of the interiors of Brandenburg House. The book quotes William Locke's Bon Ton Magazine first published in 1791 which described the house in 1792 as having been bought for £8,000 with the final cost following restoration exceeding £12,000; he notes "A new service of gilt plate has been likewise making for some months past. (A. M. Broadley and L. Melville, op. cit., vol. 1, p. lxxxvii). The introduction also describes the birthday celebration for the Margrave in 1803 as being 'the most magnificent ever given at Brandenburgh House. The service of plate displayed was valued at £18,000.' (ibid., p. ciii).