The Mozart family arrived in London on 23 Apr 1764 and departed on 24 Jul 1765, a period of 15 months, by far their longest stay anywhere on their European tour. During that time the Mozart children made three appearances at court (27 Apr, 19 May, and 25 Oct 1764) and gave three public concerts (5 Jun 1764 in the Great Room at Spring Garden, 21 Feb 1765 in the Little Theatre in Haymarket, and 13 May 1765 in Hickford’s Great Room). Wolfgang also performed a concerto on the organ at a charity concert at Ranelagh House on 29 Jun 1764. In July, shortly before their departure, the Mozart children appeared daily for one week in the Great Room at the Swan and Hoop Tavern. We can be reasonably certain that this is a complete accounting of their public appearances and their appearances at court.

On the other hand, the Mozarts’ performances at private concerts and functions in London are much less well documented. In the extract above, Margaret Maskelyne, Lady Clive, writes to her husband Robert in India that she is giving a concert the following day, Wed, 13 Mar 1765, at their house on Berkeley Square in London. Participating in the concert, she writes, will be the celebrated castrato Giovanni Manzoli (accompanied by John Burton on the harpsichord) and the Mozart children. This passage in Lady Clive’s letter was discovered by Ian Woodfield, who published an article about it in Music & Letters in 1995.

Margaret Clive, née Maskelyne (1735–1817) was the sister of Nevil Maskelyne (1732–1811), a clergyman and noted astronomer, who was appointed Astronomer Royal on 26 Feb 1765, just a little over two weeks before Lady Clive’s concert. Margaret’s husband was Robert Clive, the famous (or infamous) “Clive of India” (1725–1774), who was instrumental in the consolidation of British power on the Indian subcontinent, becoming wealthy in the process; he was made Baron Clive in 1762. At the beginning of June the previous year, Clive had departed for his third extended excursion to India; the original plan had been that Lady Clive would accompany him, but in the event she did not, apparently because she was pregnant (Templeton 2016, 63).

The position of Lady Clive’s name in Leopold Mozart’s travel notes suggests that they met her around the time of the concert (Briefe, i:194; Schurig 1920, 36). Her concert on 13 Mar 1764 took place at her home in Berkeley Square (no. 45), probably in the Great Drawing Room (Woodfield 1995, 196). Robert Clive died in this house in 1774; it is variously said that he committed suicide or died from the effects of opium taken to alleviate the pain of gallstones.

We do not know the program of Lady Clive’s concert, but Woodfield (1995, 202) speculates that Wolfgang might have performed items from his Six Sonatas for Harpsichord, Violin, and Cello, op. 3 (K. 10–15). The dedication of that set to Queen Charlotte is dated 18 Jan 1765 (Dokumente, 39–40), and the sonatas were first advertised on 20 Mar 1765, just one week after Lady Clive’s concert (Dokumente, 43). As Woodfield points out, the British Library preserves a copy of the first edition of op. 3 that formerly belonged to the Clives (Hirsch IV.3a). He goes on to speculate that Wolfgang and Nannerl might also have performed the four-hand sonata, K. 19d (the authenticity of which remains uncertain), or a concerto for two keyboards by Wagenseil (Woodfield 1995, 203).

On 11 Mar 1765, the day before Lady Clive’s letter to her husband, an advertisement had appeared in The Public Advertiser announcing the Mozarts’ intention to give a final public concert “before their Departure from England” (Dokumente, 43); this concert eventually took place on 13 May 1765. In her letter, Lady Clive gives the ages of the children as 8 and 12, matching the ages given in the advertisement; but Wolfgang and Nannerl were in fact 9 and 13 at the time (for more on the advertised ages of the Mozart children, see our entries for 21 Jan 1765 and 10 May 1765).

Lady Clive’s concert also featured the castrato Giovanni Manzoli (also often “Manzuoli”, c. 1720–1782; on Manzoli see also Hansell 2001 and Rice 2004). Manzoli had been engaged by the King’s Theater in London for the season 1764/65, making his debut to tremendous acclaim on 24 Nov 1764 in the pasticcio Ezio. Leopold Mozart first mentions Manzoli in a letter to Lorenz Hagenauer on 8 Feb 1765 (Briefe, i:178–79), writing somewhat enviously of the great sums the singer was earning in London. Manzoli’s name also appears in Leopold’s travel notes (Briefe, i:194; Schurig 1920, 35).

Baron Grimm, in an article in Correspondance littéraire dated 15 Jul 1766, mentions how greatly Wolfgang had benefited from hearing Manzoli sing during the winter of 1764/65:

Ayant entendu Manzuoli à Londres pendant tout un hiver, il en a si bien profité que, quoiqu’il ait la voix excessivement faible, il chante avec autant de goût que d’âme. [Theroux 1879, 82; Dokumente, 55]

Having heard Manzoli in London through an entire winter, he has benefited so much that even though he has an extremely weak voice, he sings with equally as much taste and feeling.

Daines Barrington, as part of his examination of young Wolfgang in June 1765, famously asked the boy to improvise arias of love and rage in the manner of Manzoli (Barrington 1771, 60–61; Dokumente, 89).

Lady Clive refers to “Manzoli’s benefit.” On Thu, 7 Mar 1765, just five days before the date of her letter, Manzoli had given a performance for his own benefit of Giardini’s ll re pastore, composed especially for the occasion.

Following his season in London, Manzoli retired from the stage and took a position as chamber singer at the court of Grand Duke Leopold in Florence (on this portion of the singer’s career, see Rice 2014). He came out of retirement in 1771 to sing in the productions of Hasse’s Ruggiero and Mozart’s Ascanio in Alba, both commissioned for the wedding in Milan of Archduke Ferdinand and Princess Maria Beatrice of Modena in the fall of 1771 (see Tagliavini 1956, vii and passim, and Rice 2004).

Also mentioned in Lady Clive’s letter is the harpsichordist and composer John Burton (1730–1782), whose name likewise appears in Leopold’s travel notes (“Mr: Borton Clavierist”; Briefe, i:196 and Schurig 1920, 38). Woodfield (1995, 195) speculates that one of the “Fidlers” mentioned in her letter may have been Tommaso Mazzinghi, whose name appears in Leopold’s travel notes immediately before Lady Clive’s.