This report provides new information about the Mozarts’ activities in Brussels. The family arrived in the city on 4 Oct 1763, and stayed six weeks before departing for Paris on 15 Nov. Leopold attempted to cultivate the favour of Prince Charles of Lorraine, the Governor of the Austrian Netherlands, as Leopold related to Hagenauer on 4 Nov:

Nun sind wir schon bald 3 wochen in Brüssel aufgehalten, und der Prinz Carl hat mit mir selbst gesprochen, und gesagt, daß er in einigen Tagen meine Kinder hören will, und doch ist noch nichts geschehen. ja, es hat das Ansehen, daß gar nichts daraus wird, denn der Hr: Prinz thut nichts als jagen, fressen und sauffen, und am Ende kommt heraus, daß er kein geld hat. Entzwischen habe ich mit guter art von hier weder abreisen, noch ein concert geben können, weil ich, auf das eigene Wort des Prinzen, seinen Entschluß habe abwarten müssen. [Briefe, i:108]

We then stayed in Brussels for three weeks, and Prince Charles himself spoke with me, and said that he wished to hear my children in a few days, and yet nothing has happened so far. Yes, it looks as if nothing at all will come of it, for the Herr Prince does nothing but hunt, gorge, and booze, and in the end it turns out he has no money. In the meantime, I have been unable, from good manners, either to leave here or to give a concert, because on the word of the Prince himself I had to await his decision.

Later in the letter, after detailing some of the gifts the children had received, Leopold continues: “Nun habe zwar Hofnung künftigen Montag da ein grosses Concert seyn wird, eine gute beute von grossen thalern und louisd’or zu machen” (“We now have hopes that there will be a grand concert this coming Monday, taking a good purse of grand thaler and Louis d’or”). A letter from Paris a month later confirms that a concert had indeed taken place in the presence of Prince Charles, without mentioning a date or location (Briefe, i:113). No other reports of the Mozarts in Brussels are known.

The “coming Monday” was 7 Nov (not 7 Oct, as given in Eibl, Addenda, 7). Yet the above report has the family giving a successful concert in the Salle du Concert Bourgeois on 9 Nov. There are three possible interpretations of this conflicting information: Leopold’s anticipated concert was delayed by two days, the newspaper’s date was incorrect, or the family in fact gave two concerts (note that although the dateline is 15 Nov, the correspondent must have been writing on 10 Nov, as 9 Nov was “gestern”). It is not clear whether the concert(s) were the fulfillment of Prince Charles’ intention to hear the children or whether he also held a private audience.

The Concert Bourgeois was a Brussels musical society founded in 1754. In 1756 the society established a concert hall in the “Petite Boucherie”, located on place de Bavière (today place de Dinant); it was here that the Mozarts’ concert evidently took place.

The building was turned into a Maison du Peuple in 1886 (not to be confused with the more celebrated building of that name) and demolished in 1955 (see Cornaz 1999).

The unusual “qui Sant l’uniques” is apparently a corrupt form of “qui sont uniques”, and may imply that the original report was in French. The source of the correspondent’s information about the family’s earlier performances in Schwetzingen, Frankfurt, Mainz and Koblenz is unknown; no newspaper reports are known to survive, apart from two advertisements in the Frankfurt press (Dokumente, 25–26).

We are grateful to Kris Steyaert for his assistance with this entry.