This reference to Mozart in the diary of Count Karl von Zinzendorf is not in Dokumente, Addenda, or Neue Folge. It was discovered by Mary Sue Morrow, who includes the event in her 1989 book on Viennese concert life, although she does not transcribe Zinzendorf’s entry (Morrow 1989, 372). It is only the second known document referring to Mozart after his arrival in Vienna on 16 Mar 1781, following the composer’s own letter of 17 Mar.

Mozart came directly to Vienna from Munich, where he had been staying since early November for the completion, rehearsal, premiere, and aftermath of his opera Idomeneo. In March, Mozart was evidently summoned to Vienna by his employer, the Archbishop of Salzburg, Count Hieronymus Colloredo von Waldsee und Mels (1732–1812), although this summons is not directly documented. Exactly why the Archbishop had gone to Vienna remains unclear. Jahn (1867, i:608) suggests that the trip may have been occasioned by the death of Empress Maria Theresia. But while her death was perhaps a motivating factor, it may not have been the main reason.

Maria Theresia died on 29 Nov 1780; her exequies were held in St. Stephen’s Cathedral two months later, on 29, 30, and 31 Jan 1781 (see the description in the Wiener Zeitung, 7 Feb 1781). The notion that the Archbishop might go to Vienna during the mourning period was already circulating in the Salzburg rumor mill at least as early as 18 Dec 1780 (see Nannerl Mozart’s letter to her brother of that date, Briefe, iii:62, quoted in the Notes below), and a small contingent of the Archbishop’s staff left for Vienna on 11 Jan 1781 (see Leopold Mozart’s letter that day, Briefe, iii:87–88). Leopold writes at one point that Colloredo was scheduled to leave on 20 or 22 Jan (Briefe, iii:88), which would have brought him to Vienna in time for the exequies. Yet the Archbishop himself seems to have dithered about his departure. According to Zauner’s Chronik von Salzburg (1826, xi/1:651, no source given), he did not leave Salzburg until 21 Feb 1781, three weeks after the Empress’s exequies. Whatever the actual date of his departure, he subsequently remained in Vienna for several months, lodging in the Deutschordenshaus, and returning to Salzburg (according to Zauner) only on 8 Jun.

Colloredo did not bring a large staff to Vienna for his stay. In a letter of 11 Jan, Leopold Mozart mentions eight staff by their functions (without naming them), plus Joseph Cassel as Kammerportier (Cassel was also a violonist in the Archbishop’s Kapelle), and Oberstküchenmeister Count Karl Joseph Maria Felix von Arco (1743–1830), son of the Mozarts’ patron Count Georg and the only noble accompanying Colloredo to Vienna. In Wolfgang’s first letter from Vienna on 17 Mar, he describes dining together with six of the Archbishop’s staff, plus violinist Antonio Brunetti (ca. 1744–1786) and castrato Francesco Ceccarelli (ca. 1752–1814). As far as we know, Mozart, Brunetti, and Ceccarelli were the only musicians from the Salzburg Kapelle brought to Vienna specifically in their capacity as musicians. Cassel might also have doubled as a musician in performances, and it may be that one or two of the other staff also doubled as instrumentalists, although this is speculative.

In any case, the Archbishop clearly did not bring a full contingent of musicians to Vienna, and any larger ensembles for musical events that he hosted must have been staffed, at least in part, by local musicians. Wolfgang seems to allude to such pick-up groups in his letter to his father on 28 Apr 1781 (Briefe, iii:108):

gestern war grosse accademie bey uns—vermutlich die letzte;—
die accademie ist recht gut ausgefallen, und trotz all den Hindernüssen
seiner Erzbischöflichen Gnaden habe ich doch ein besseres Orchestre
gehabt, als Brunetti, das wird ihnen Ceccarelli sagen; [...]

Yesterday we had a grand academy—presumably the last—
The academy went quite well, and in spite of all of the hindrances of
His Grace the Archbishop, I had a better orchestra than Brunetti,
as Ceccarelli will tell you [...]

By this point, Brunetti had already been allowed to return to Salzburg. Mozart is implying that Brunetti had previously been responsible for assembling and directing the orchestras for the Archbishop’s previous musical events in Vienna, but that this responsibility had fallen to Mozart after Brunetti’s departure.

In his first letter to Salzburg from Vienna on 17 Mar 1781, Mozart writes that the Archbishop’s musicians had already given a concert at 4 in the afternoon the previous day, the day of Mozart’s arrival. His wording seems to imply that this was the first concert given by Colloredo in Vienna, and no earlier concert is known:

gestern um 4 uhr habe wir schon Musick gehabt—da waren ganz
gewis 20 Personnen von der grösten Noblesse da—Ceccarelli
hat schon beym Balfi singen müssen—heute müssen wir zum
fürst Gallizin—der gestern auch da war— [Briefe, iii:94]

Yesterday at 4 we already had music—indeed, 20 people from
the highest nobility were there—Ceccarelli already had to sing at
Palffy’s—today we have to go to Prince Golitsyn’s—who was also
there yesterday—

“Ceccarelli already had to sing at [Count] Palffy’s” may imply that the castrato was the first of the Archbishop’s musicians to perform anywhere in Vienna following their arrival. However, that performance was not hosted by the Archbishop.

In his diary entry transcribed above, Zinzendorf reports hearing music while dining with Colloredo and other guests in the Deutschordenshaus on Fri, 23 Mar 1781, exactly one week after the Archbishop’s first concert. Zinzendorf is our only source for the event; Wolfgang mentions nothing about music in his letter to his father the following day. But Zinzendorf’s entry raises several questions.

If the Archbishop had brought only his star soloists to Vienna—Mozart, Brunetti, and Ceccarelli—then why would Mozart have been playing violin on 23 Mar, rather than Brunetti? So far as we know, Zinzendorf had not seen Mozart since the family’s first trip to Vienna in 1762–1763, when Wolfgang was a child (the count had not been in Vienna when Mozart visited in 1767–1768 and 1773–1774); so we cannot rule out the possibility that Zinzendorf was simply mistaken at his first encounter in 1781: in other words, it might have been Brunetti playing the violin. Although Mozart was undoubtedly present, Zinzendorf may simply not have recognized at that point which man was which. If, on the other hand, Mozart did play the violin, it would be the only known case of his performing solo on that instrument during his final decade in Vienna.

We can only speculate at this point whether the violinist (Mozart or Brunetti) or Ceccarelli performed any works by Mozart on 23 Mar: we do not know precisely which of his compositions Mozart had brought with him when he arrived in Vienna in 1781 (although he presumably had the autograph of Idomeneo). So far as we know, he had not composed any new music in Vienna between his arrival on 16 Mar and the performance one week later.

Zinzendorf also reports that two oboists “flayed” (“ecorcherent”) the company’s ears during the meal. The principal oboists in the Archbishop’s Kapelle in 1781 were Joseph Fiala (1748–1816) and Ludwig Feiner (dates unknown; see Hintermaier 1972, 112–16 and 98–99 respectively). However, Fiala seems not to have gone to Vienna with the Archbishop: in fact Mozart, in his letter of 24 Mar, sends his greetings to Fiala in Salzburg (Briefe, iii:100). Since 9 Jan 1780, Feiner had held a joint position in the Archbishop’s staff as violinist and Kammerportier (Hintermaier 1972, 98). So he might well have gone to Vienna with Colloredo in a double capacity, but we at present have no evidence that he did; his name does not appear in any of the Mozart family’s correspondence from around this time. Two other members of the Archbishop’s staff in 1781 had positions as “Hoffagottist und -oboist”: Melchior Sandmayr (1728–1810) and Johann Heinrich Schulz (ca. 1716–1790). But neither held additional staff positions, and there is, in any case, no evidence that Sandmayr or Schulz came to Vienna in 1781.

Another possibility, albeit speculative, is Friedrich Ramm (1744–1813), one of the leading oboists in Europe at the time, for whom Mozart had composed several works. Ramm happened to be in Vienna at the time and had just given a public concert: Mozart mentions in his letter of 24 Mar 1781 that Ramm sends his greetings (Briefe, iii:100). Mozart might have used his prior friendship with Ramm to persuade the oboist to make an appearance at the Archbishop’s. Zinzendorf’s negative reaction does not necessarily imply that the oboists who played on 23 Mar were bad; he simply might not have been used to having oboists playing nearby in a resonant room.

One has the impression that Zinzendorf lists everyone who attended the meal; if so it was a fairly intimate affair, with only six guests in addition to the Archbishop. “Gundaccar” was the Archbishop’s older brother, Prince (Fürst) Franz de Paula Gundaccar von Colloredo-Mansfeld (1731–1807). “Taroucca” was Count Franz Stephan Sylva-Taroucca (also Tarouca, 1750–1797). “M:^e de Wilczek” was perhaps Countess Rosalia von Wilczek (née Schulz, 1760–1831), wife of the Austrian military man Count Joseph Augustin von Wilczek (1746–1828), although there are other possibilities. Zinzendorf’s “brothers” (“confreres”) in the Deutscher Orden “Harrach et Erpach” were Count Alois Ernst von Harrach (1728–1800) and Count Christian zu Erbach-Schönburg (1728–1800), both members of the order and at various times officials in the order’s Austrian “bailiwick.” “Uberacker” may have been Count Wolfgang Christoph von Uiberacker (1736–1801).

At present, Archbishop Colloredo is known to have hosted only two more musical events during his stay in Vienna, in addition to those on 16 and 23 Mar 1781: a concert on 8 Apr—for which Mozart composed the Rondeau for violin, K. 373 (for Brunetti), the Sonata for Keyboard and Violin, K. 379 (for himself and Brunetti), and the Recitative and Aria, K. 374 (for Ceccarelli)—and another on 27 Apr, about which nothing is known other than that it included an orchestra.