Adam Smith is mentioned twice in Horace Walpole’s journal entry for Monday, April 7: “The Rena, Lord Tavistock and Mr Smith came. To Madame du Deffand. To Hotel de Brancas…. Supped at Lady Mary Chabot’s with Lady Browne, Mme de Bouzols, Mr Smith and Chevalier de Barfort.” Of all of people mentioned in this entry, La Rena, a high-class prostitute or “courtesan,” was the most scandalous. A footnote identifies her as “… the Countess L__________, an Italian separated from her husband. She was mistress to the [Earl] of March.” Two additional sources support this identification: (1) “John Robert Robinson, ‘Old Q,’ 1895, p. 78,” and (2) a letter from Horace Walpole to Sir Horace Mann dated April 14, 1769, in which Walpole himself states that “she was wife of a Florentine wine-merchant and former mistress of Lord Pembroke.” As it happens, Walpole may have known La Rena as early as 1762, when he refers to her as a “fashionable courtezan” in a footnote to his published correspondence from that year.
La Rena apparently had many admirers; a “Lord March” refers to her in glowing terms in a letter address to George Selwyn dated Nov. 17, 1766. But what was a kept woman, an exotic foreign-born courtesan, doing at the Hotel du Parc Royal, where both Walpole and Smith (and perhaps Tavistock) were lodging, and did she and Adam Smith ever meet? It’s possible, of course, that she was mistress to Lord Tavistock, the second person mentioned in Walpole’s April 7 entry.
But who was Tavistock, and what is his possible relationship to Adam Smith? Lord Tavistock could refer to Francis Russell (1739–1767), whose portrait is pictured below, who was the Marquess of Tavistock and the eldest son of the 4th Duke of Bedford. Like Walpole and Lyttelton, Tavistock was sat in the House of Commons (1761 to 1767), but he would die in 1767 at the age of 28 after falling from his horse while hunting. [As an aside, Colbert de Castle-Hill’s father had died the same way in 1746.]
What if, however, La Rena was Adam Smith or Duke Henry’s mistress during this time? Although such a scenario might sound unlikely or implausible at best, it is not altogether beyond the realm of possibility. At the very least, perhaps Adam Smith and La Rena met that day (April 7, 1766). If so, what did they discuss? Perhaps Smith asked her about her diet and her favorite foods. Although Smith does not openly discuss the market for prostitution in The Wealth of Nations, In Chapter 11 of Book 1 of his magnum opus, in the subsection titled “Of the Produce of Land which always affords Rent,” Smith writes:
“… experience would seem to show that the food of the common people in Scotland is not so suitable to the human constitution as that of their neighbours of the same rank in England. But it seems to be otherwise with potatoes. The chairmen, porters, and coalheavers in London, and those unfortunate women who live by prostitution, the strongest men and the most beautiful women perhaps in the British dominions, are said to be the greater part of them from the lowest rank of people in Ireland, who are generally fed with this root. No food can afford a more decisive proof of its nourishing quality, or of its being peculiarly suitable to the health of the human constitution."
There are no references to prostitutes or prostitution in The Theory of Moral Sentitments. So, how did Smith know about the diets of “those unfortunate women who live by prostitution”? Perhaps, he asked.
 Lewis 1939, p. 312, footnote omitted.
 Ibid., p. 312 n. 294. See also Hicks 2002, p. 69. The Earl of March is further identified in a footnote to Horace Walpole’s letter to the Earl of Hertford dated Nov. 25, 1764 (Letter 233), which is published in Walpole 1840, pp. 467-471. Specifically, this note reads: “James, third Earl of March, a lord of the bedchamber, who subsequently, in 1778, succeeded to the dukedom of Queensberry, and was the last of that title.” See ibid., p. 470 n.1. Among other things, the Earl of March was appointed Vice Admiral of Scotland from 1767 to 1776, and he became one of the wealthiest men in Britain, owning £1M (equivalent to £100,400,000 in 2020). See The Guardian 1999.
 Lewis 1939, p. 312 n. 294.
 See letter from Horace Walpole to H. S. Conway dated Sept. 9, 1762 (Letter 134), published in Walpole 1840, pp. 235-237. See ibid., p. 237, n. 1. See also The Spectator 1843a, p. 639.
 See The Spectator 1843b, p. 496.
 See Beatson 1807, p. 514.
 Wells 2014, p. 500.
 See, e.g., Guerra-Pujol 2020.
 The Wealth of Nations, Glasgow edition p. 177 (para. 41).