In 1790, Franz Friedrich Sigismund August Böcklin von Böcklinsau published Beyträge zur Geschichte der Musik. The title is misleading: the book consists of 20 rambling letters that Böcklin had (or at least claims to have) written to various correspondents on an assortment of musical topics with no particular unifying theme, mostly having little to do with the history of music per se, but containing a variety of tidbits about musical life in various places. Dokumente includes two short extracts from this book: one from the second letter, referring to “Gluck, Salieri, Mozard” as “splendid” (“fürtrefflich”) composers; and another that does not refer to Mozart, but praises church music in Salzburg while depicting the “Concert-Orchester” in the city as mediocre (Dokumente, 335–36). Two further references to Mozart in the fifteenth and sixteenth letters of Böcklin’s Beyträge are given in Neue Folge (124).

Deutsch and Eisen overlooked yet another reference to Mozart, in Böcklin’s first letter. That reference is transcribed and translated above.

Amphion and Orpheus are figures from ancient Greek mythology who are especially associated with music. Orpheus was said to have been able to charm wild beasts with his playing and singing, and he used the power of his music to persuade the King of the Underworld to allow him to retrieve his beloved Euridice. Amphion and his twin brother Zethus were the sons of Antiope and Zeus. Together Amphion and Zethus conquered Thebes, became its rulers, and built its walls. Amphion had been taught to play the lyre by Hermes, who gave him a golden lyre. According to myth, the sound of Amphion’s lyre alone caused stones to form themselves into the walls of Thebes.

“Hayde” refers to Haydn, almost certainly Joseph; Böcklin fairly consistently spells the name “Hayde” or “Haide” throughout the Beyträge. “Schmidtbauer” is probably Joseph Aloys Schmittbaur. The other musicians named along with Mozart are Antonio Salieri, Georg Joseph Vogler, and Ignaz Pleyel.

Böcklin’s second and third references to Mozart occur in the second letter, in a passage on the power of the human voice in opera. The letter as a whole has to do with musical life in Vienna. The extract in Dokumente does not provide sufficient context to make clear that Böcklin is comparing the operatic music of the three composers. Here is the passage with more of the surrounding context:

[17]

⁣        Zweyter Brief.
        An Hrn. v. D. *
        Wien.
        [...]

[19] [the passages not in Dokumente are in blue]

⁣    Es ist fast ungläublich, — was eine gute,
wohlbegleitete Menschenstimme wirke! Unsere mora=
lischen Schriftsteller, die so sehr wider das Theater
eifern, stellen es uns eben daher genug vor, wie
viel Gewalt die Musik über unsere Seelen habe. —
    Gluck, Salieri, Mozard, welche fürtreffliche
Künstler sind das nicht? — Ich wünschte, sie
hörten solche. — Denn in der Abwesenheit, läßt
sich auch davon nichts gründliches urtheilen, noch
sagen. —
    Salieri und Mozard sind glücklicher im Ausdruck
der sanften — als der starken Leidenschaften. —
    Ritter von Gluck hingegen, für die Tonkunst
ein Rubens, — besitzt eine, ihm eigene Kühnheit
und Stärke des Ausdrucks, anneben aber auch eine
frappante Mannigfaltigkeit, und geschickte Anwen=
dungskunst seiner Gänge und Schlußfälle, die ich
noch nirgends angetroffen habe. [...]
[Böcklin, Beyträge, 19]

[translation:]

⁣    It is almost unbelievable, the effect that
a well-accompanied human voice can have!
Our writers on morals, who rail so strongly
against the theater, thus also show
us well enough how great is the power
that music has over our souls.—
    Gluck, Salieri, Mozart, what splendid artists,
are they not?— I wish that you heard
such as they.— For in their absence,
no definite opinion can be formed, nor
expressed.
    Salieri and Mozart are more successful in
the expression of tender passions than in strong
ones.
    Ritter von Gluck, on the other hand, a Rubens
of musical art, possesses his own particular
audacity and strength of expression, but also
in addition a striking diversity, and skillful
application of his passages and cadences,
which I have met with nowhere else. [...]

On the previous page, Böcklin writes that the first opera he heard in Vienna was Gluck’s Alceste. The opera, which had been premiered in Vienna in 1767, was revived in Dec 1781 for the joint visits to Vienna of Grand Duke Paul of Russia and his wife, and Duke Friedrich Eugen of Württemberg and his wife, son, and daughter (see our entry for 8 Oct 1782). After its gala performance at Schönbrunn on 25 Nov 1781, Alceste was given eight times in the Burgtheater over the next three months. The production then received five further performances in Jan and Feb 1783; in the eighth letter of the Beyträge, Böcklin notes that he was Vienna in 1783, and it may have been one or more of the performances in that last group that he attended (for more on Böcklin’s sojourn in Vienna, see the biographical sketch below).

In the eighth letter Böcklin tells of visiting Gluck often while in Vienna, and claims to have continued to correspond with him until shortly before Gluck’s death in 1787. Böcklin also writes in the second letter of having heard Aloysia Lange in the role of Alceste:

⁣⁣                                    — Hier that die berühmte Lan=
ginn gleichsam Wunder mit ihrer feinsten Kehle, und
da ward ich von neuem überzeugt, daß gute Kehlen
wohl accompagnirt werden müssen (so wie es auch
hier geschiehet) wann sie Wirkung thun sollen. —
[Böcklin, Beyträge, 18]

⁣⁣                                    — Here the famous Lange seemed
to do miracles with her most subtle throat, and I was
once again convinced that good throats must be
accompanied well (as happened here), if they
are to have their effect.

He mentions having also heard Mara in Vienna; in the 1780s, however, Mara is known to have performed in Vienna only in Sep 1780 and early spring 1781 (see Morrow 1989, 248–49, 373). It may be, then, that Böcklin was in Vienna earlier than 1783, or it may be that he heard Mara somewhere else and misremembered. In any case, he reports in his second letter that he prefers Lange to Mara:

Indessen finde ich, daß das Gesange derselben [Mara]
nicht so ausdrückend und rührend, als der gedachten
Wiener Sängerinn seye, — deren Stimme einer
Cremoneser Geige ähnlich ist, — und immer ge=
fällt. [Böcklin, Beyträge, 18–19]

However, I find the singing of the latter [Mara]
not so expressive and moving as the Viennese
singer I mentioned—whose voice is similar to
a Cremonese violin—and always pleases.

It is likely that Die Entführung aus dem Serail would have been the only opera by Mozart that Böcklin would have had the opportunity to hear by that point. It was first performed on 16 Jul 1782, and was frequently performed through the beginning of Feb 1783.

Two other references to Mozart are found in Böcklin’s fifteenth and sixteenth letters; both references are given in Neue Folge (124). The first includes Mozart in a list of composers whose music had been performed at concerts in Freiburg am Breisgau (Böcklin, Beyträge, 110). The second includes Mozart in a long list of composers whose symphonies had been performed at the Benedictine monastery at Ettenheimmünster (Böcklin, Beyträge, 123–24).

Böcklin: A biographical sketch

Franz Friedrich Sigismund August Freiherr Böcklin von Böcklinsau (also “Boecklin” or “Boeklin”; 1745–1813) was born in Strasbourg in 1745 to an old Alsatian family (on the Böcklin family, see principally Kageneck 1994, 108–12).

Böcklin has the dubious distinction that Ernst Ludwig Gerber, in the 1812 edition of his Lexikon, retracted and disowned the long and effusive entry on him in the original 1790 edition (Gerber 1790, col. 176–78; Gerber 1812, col. 447–48). In fact, Gerber devotes a full column to his retraction, expressing his mortification and outrage at having been fooled into publishing an article in the 1790 Lexikon that subsequently proved to have been based on dubious or false information. At the end of the 1790 article he had noted that it was based on an article about Böcklin published the previous year in Bossler’s Musikalische Real-Zeitung. That article was attributed to a “Pf. Christmann” (“Pfarrer Christmann”), under the title “Sendschreiben eines unpartheiischen Musenfreunde an die Herausgeber der musik. Realz” (“Open letter by an impartial friend of the arts to the editor of the Musikalische Real-Zeitung”; Christmann 1789, cols. 150–52, cols. 154–56). This missive, nearly five full columns in length printed over two issues, is a florid panegyric to the outstanding musical talent and compositions of the (allegedly) exceedingly modest and generous Böcklin, whom the author calls a “Tonsezer vom ersten Rang” (“a composer of the first rank”). In his article for the 1790 Lexikon, Gerber toned down the rhetoric slightly, but otherwise reproduced more or less completely what he took to be the article’s factual content. “Christmann” claimed that Böcklin had been a pupil of Schobert in keyboard, and of Jommelli and Franz Xaver Richter in composition. The article attributes several singspiels to Böcklin, as well as a (supposedly well-received) published collection of songs, numerous symphonies, and a significant body of church music, chorales, and odes. “Christmann” expresses the view that too little of Böcklin’s work had been published, probably owing to the composer’s excessive modesty.

In 1790 a genially devastating review of Böcklin’s Beyträge was published in twelve full columns across two issues of Bossler’s Musikalische Korrespondenz, the successor to the Real-Zeitung. The review dismantles Böcklin’s letters one by one, highlighting the author’s sometimes ill-informed and occasionally downright peculiar opinions. For instance, the reviewer dismisses Böcklin’s easily refutable claim that the harmonies in Dittersdorf’s symphonies are “richer” than those in Joseph Haydn’s. The reviewer also points out numerous infelicities in Böcklin’s grammar and vocabulary (Anonymous 1790).

Oddly, in Mar 1792 the Musikalische Korrespondenz published another anonymous panegyric to Böcklin (the author is identified as “P.”) closely based on the one published in 1789; many passages in the two are essentially identical, and the 1792 article includes very little new information. It is difficult to fathom how the near identity of the two articles could have escaped the notice of Bossler, the publisher of both papers. The following month, another review of Böcklin’s Beyträge appeared, this time in the Allgemeine Literatur-Zeitung. It is shorter than the one in the Korrespondenz, but scathing and perhaps even more devastating. Gerber cites all four articles—the two nearly identical panegyrics and the two negative reviews—in his retraction in 1812. Evidently the reviews had tipped him off that the “Christmann” article from 1789 could not be trusted.

Anyone today who reads the Beyträge and the two panegyrics will immediately recognize the highly similar style: ornate and grandiloquent, with frequent digressions, and idiosyncratic in vocabulary and grammar. Especially striking is the suspicious use in both Böcklin’s book and the “Christmann” panegyric of the rare word “Saitenbändiger” (meaning “the player of a stringed instrument”; see Grimm). In fact, the 1790 review of Böcklin’s Beyträge had noted that “Saitenbändiger” seemed to be a “Lieblingswort” of the author.

In preparing the article on Böcklin for his 1790 Lexikon, Gerber had naturally assumed that “Pf. Christmann” was Johann Friedrich Christmann (1752–1817), who was indeed a “Pfarrer” (pastor) and a composer living in Ludwigsburg, where Böcklin himself had apparently also lived in the early 1770s. Gerber’s 1812 Lexikon includes a fairly long article on Christmann (Gerber 1812, i:715–17), and Gerber probably knew that Christmann also wrote about music: in Nov 1790, for example, the Musikalische Korrespondenz published a report on Sixt Bachmann under Christmann’s name (one assumes legitimately); the article refers at one point to young Mozart, in a passage quoted in Dokumente (333).

In his 1812 retraction, Gerber writes that he now doubts Christmann’s authorship of the article on Böcklin published in the Musikalische Real-Zeitung in 1789:

[...]                                           Ich nehme
hier feierlichst mein Wort, am Ende des
Boeklinschen Artikels im a. Lex. wieder zu=
rück, als ob Hr. Pf. Christmann eines
solchen Gewäsches fähig sey. Eher wollte
ich es der Eitelkeit u. s. w. des Hrn. von
Boeklin zutrauen, sie selbst aufgesetzt
zu haben. [...]
[Gerber 1812, col. 447]

[...]                                          I formally
retract my words at the end of the
Böcklin article in the Altes Lexikon; as if
Herr Pfarrer Christmann could be capable
of such claptrap. I would rather give credit
to the vanity etc. of Herr von Böcklin as
having drafted it himself. [...]

Although conclusive evidence is lacking, it seems likely that the supposedly “modest” Böcklin had composed a panegyric to himself, or perhaps duped or charmed Christmann into submitting under his own name an article that had largely been written by Böcklin. It seems, then, that considerable skepticism is called for in assessing the supposedly factual content of the “Christmann” article on Böcklin. Yet the “facts” of that article, reproduced in Gerber’s 1790 article on Böcklin, still form the basis of current writing on Böcklin’s musical biography.

In fact, the “Christmann” panegyric and the slightly more sober version of it published by Gerber seem to be the only known sources for Böcklin’s musical biography. Even recent writers on Böcklin who are aware of Gerber’s later retraction nevertheless rely on the dubious information in Gerber’s original article. The article on Böcklin by Count Kageneck (whose mother was a Böcklin) is richly informative about many aspects of Böcklin’s complicated and unhappy family life, although the article cites no sources (Kageneck 1994, posthumously published). Whatever sources Kageneck may have used for the other parts of his article, his treatment of Böcklin’s musical life is based almost entirely on Gerber, and Kageneck seems to take the “facts” in Gerber’s article at face value (Kageneck 1994, 123–24). Similarly, Schmider, whose approach is generally cautious—he even begins his article with a long quotation from Gerber’s retraction—nevertheless accepts the same dubious body of “facts” about Böcklin’s musical biography that ultimately derive from the retracted article (Schmider 2004; Schmider cites Kageneck as his source for some of these “facts”). All things considered, then, it is probably best, in the absence of independent corroborating evidence, to remain skeptical of all apparent statements of fact regarding Böcklin in the “Christmann” article and in Gerber’s article in the 1790 Lexikon.

Böcklin was the only child of Franz Jacob Christian Böcklin and Charlotte von Dungern, who had married in Nov 1744. (The following biographical sketch is based principally on Kageneck 1994.) Their son was born in Sep 1745; the couple formally separated in 1750. The mother’s subsequent life was the subject of scandal: she appears to have had more than one lover, and she lived openly with Friedrich Ferdinand Johann von Mundolsheim, with whom she had illegitimate children, although young Böcklin did not learn of the existence of his half-siblings until later. When Böcklin was 15 (thus around 1760), his father sent him to the University in Strasbourg, where he studied constitutional law (Staatsrecht), history, and botany. Böcklin’s father died in 1762; as the son had not yet reached his majority, he was placed under the guardianship of Philipp Reinhard von Berstett. After Böcklin completed his studies in Strasbourg, Berstett sent him on an educational trip to Italy. As the sole legitimate male offspring of this branch of the Böcklin clan, young Franz Friedrich Sigismund August inherited the family’s estate in Rust in Ortenau (today part of Baden-Württemberg); the family’s castle in Rust, Schloss Balthasar, survives, and is today part of the Europa-Park. He also inherited his father’s considerable debts.

In 1765, Böcklin married Caroline Roeder von Diersburg; their marriage was combative and unhappy, but they had 11 children, six of whom lived to adulthood. Böcklin celebrated his majority and accession to his estate in 1770. In 1771, in urgent need of income to pay off his father’s debts, he made a tour of local courts looking for a paying position. He received several honorary titles but no income, including, in 1772, the unpaid position of Kammerherr at the court of Duke Ludwig von Württemberg in Ludwigsburg. Only in 1781 did Böcklin finally find a paid position, when Fürst Friedrich August von Anhalt-Zerbst named him commander (Oberst or Obrist) of his 7th Battalion. In 1783 (or perhaps in 1782) Friedrich August is said to have sent Böcklin to Vienna as his court’s ambassador; Böcklin apparently remained in the imperial capital for around a year, and it is his musical experiences in Vienna that he reports in the second letter of his Beyträge. Böcklin separated from his wife in 1781. His later years were spent with Anna Maria Herr, the daughter of a local gamekeeper and forester; the couple apparently had an illegitimate daughter. Böcklin is said to have suffered from melancholy, and he lived an increasingly withdrawn life in his last years. He died in Ettenheim (now in Baden-Württemberg) in 1813.

In addition to his numerous unpaid titles, Böcklin also collected memberships in learned societies: the Churfürstlich-baierische Gesellschaft sittlich- und landwirtschaftlicher Wissenschaften in Burghausen; the Kaiserliche Akademie der Naturforscher in Onolzbach; the Wissenschaftliche Gesellschaft in Göttigen; and the Hessen-Homburgische Gesellschaft (Kageneck 1994, 120). The “Christmann” article from 1789 notes that in 1776 Böcklin, allegedly on the strength of his musical compositions and contributions to the fine arts, had been made a member of the Accademia degli Arcadi in Rome.

Unfortunately the “Christmann” article (much of which is reproduced in Gerber’s 1790 Lexikon) appears to be the only substantial source for Böcklin’s musical biography. Yet as we have seen, there is good reason to think that Böcklin himself wrote the article or was its direct source, and it must be treated with great caution, as Böcklin gives the impression of being an unreliable witness. According to the “Christmann” article, Böcklin’s father recognized his young son’s musical talent at an early age and engaged the “best masters living at that time” (“die besten damals lebenden Meister”) to give his son instruction in singing, keyboard, and violin. One of these teachers is said to have been Johann Schobert, “until [he] went to Paris” (“bis sich jener nach Paris begab”). Little is known about Schobert’s life before Paris, where he is thought to have arrived in 1760 or 1761, so we cannot rule out the possibility that Böcklin may be telling the truth in this case. The revised panegyric printed in the Musikalische Korrespondenz in 1792 adds that Böcklin also eventually learned the flute, clarinet, and viola d’amore.

There is a significant discrepancy in the dates regarding the claim (which Böcklin repeats in the Beyträge) that he knew and studied with Jommelli at the Württemberg court in Ludwigsburg. The “Christmann” article claims that Böcklin went to Ludwigsburg at the age of 18 (thus around 1763); in his 1790 Lexikon, Gerber (unaccountably, given that his source was the “Christmann” article) writes that Böcklin went to Ludwigsburg in 1770. However, Kageneck, who should probably be regarded as the more reliable source, places Böcklin in Ludwigsburg in 1772. But Jommelli had left the service of the Württemberg court and was back in Italy by 1769 (McClymonds et al. 2015); so if Kageneck is correct, Böcklin cannot have known Jommelli in Ludwigsburg. The “Christmann” article also claims that Böcklin studied with Franz Xaver Richter in Strasbourg. These lessons, if they took place, cannot have lasted long: Richter, formerly a member of the Mannheim kapelle, first took up the position of Kapellmeister at the cathedral in Strasbourg in 1769. By this point, Böcklin was already married, had two children, and was soon to embark on his tour to find paying work in one of the local courts.

Böcklin belongs to that class of dilettantes in the eighteenth century whose intellectual and artistic interests were very wide, but whose accomplishments were negligible in all. Böcklin wrote on a wide variety of topics. His publications available on Google Books include the play Moter, oder Die Stärke der Grossmuth (1777), and the agricultural studies Vom Ursprung, Vorzügen und Hindernissen des Getreidebaues (On the Origins, Benefits, and Obstacles of Grain Cultivation, 1786), and Lob der Bienen (In Praise of Bees, 1786; for other writings by Böcklin, see Kageneck 1994, 119). In addition to his Beyträge zur Geschichte der Musik, Böcklin later published Fragmente zur höhern Musik, und für ästhetische Tonliebhaber (Fragments on Higher Music, and for Aesthetic Music Lovers, 1811); this book also contains a few references to Mozart, none of any importance.

The “Christmann” article paints Böcklin as one of the major (if unjustly neglected) composers of his age. Gerber’s article of 1790 attributes to Böcklin the operas Die Wilddiebe and Der Amtmann zu Klefeld und Der Zauberer, both from around 1780, and Das Orakel and Der Abend im Garten, the last a setting of a libretto by Böcklin himself. Both of the latter two operas are said to have been composed around 1783 under the influence of the musical theater Böcklin had experienced in Vienna. The article on Böcklin at Grove Online further attributes to Böcklin Hüon und Armand (ca. 1790), and Phädon und Naide (ca. 1790) on a libretto by Johann Georg Jacobi (Davis 2015). No music for any opera by Böcklin is known to survive apart from one song published as an insert in the Theater-Kalender for 1790: “Du bist für mich gebohren,” from his (otherwise lost) setting of Gellert’s libretto Das Orakel.

The RISM online catalog of manuscript and printed music currently includes seven entries for Böcklin. His XXIV Lieder für Junggesellen were published in 1775, and Schubart reviewed the collection in his Deutsche Chronik that same year (2. Jg, 98. Stück, 782–84). Although Schubart finds a few complimentary things to say about one of the songs, he writes:

[...]⁣    Der Herr Verfasser muß viel gute Musik,
besonders Welsche gehört, sich aber nicht sonderlich
um die Grundsätze der Harmonie bekümmert haben;
daher sind einige Melodien sehr gefällig; aber nicht
selten unharmonisch und unrythmisch. [...]

[...]⁣    The author must have heard much good music,
especially Italian, but has not especially troubled
himself about the basic rules of harmony; thus
some of his melodies are quite pleasing; but not
infrequently unharmonic and unrhythmical. [...]

He goes on to reproduce a particularly awkward vocal line in Böcklin’s setting of Miller’s “Könnt’ ich, o blühende Natur,” and goes on to say:

So ist das Lied wirklich gesetzt. Welchem An=
fänger in der Musik muß hier nicht gleich das
Unrichtige, Unrythmische, Unharmonische auf=
fallen! [...]

The song is actually set thus. What beginner
in music would not immediately notice what is
incorrect, unrhythmic, unharmonic! [...]

He also notes that the edition is full of errors:

Von Druckfehlern wimmeln diese Lieder. Die
Noten sind in Kupfer gekratzt, und sehen aus
wie Blutigel. [...]

The songs are teeming with printing errors. The
notes are scratched in copper, and look like
leeches. [...]

A review in the Allgemeinen deutsche Bibliothek (vol. 33, no. 1, 165–66) is even more brutal:

Wir wären begierig, den Sänger oder die Sängerinn zu
hören, die diese Lieder singen könnte. Die Melodie
dieser Lieder liegt oft wie lange im dreygestrichnen e und d,
dabey auf jede Note eine Sylbe: und Intervallen giebts auf
allen Seiten, die bisher noch keine menschliche Stimme rein
heraus gebracht hat. Hätte sich der Componist in dem Vor=
bericht nicht in seinem wahren Lichte gezeiget, so würden wir
die ganze Sammlung als eine Satyre über die elendesten Stü=
cke ansehen, die bisher herausgekommen: und dann würden
wir nichts daran auszusetzen finden — denn alle Fehler der
Scansion, der Declamation, des Gesanges, der Harmonie
und des Rhythmus sind so recht, wie mit muthwilligem Vor=
satz neben einander aufgestellt — als dieses, daß die Satyre
durch die völlig falsche und unsinnige musikalische Orthogra=
phie, um zu bessern, zu sehr übertrieben sey. Denn
wenn die jungen Componisten auch gleich nicht alle ganz
richtig schreiben lernen, so pflegen sie doch ihre Arbeit, ehe sie
solche dem Drucke übergeben, von ihrem Claviermeister durch=
sehen zu lassen. [...]

We would be eager to hear the male or female singer
who could sing these songs. The melodies of these
songs lie often and long around three-stroke e and d [e and d
above the treble staff], with a syllable for every note: and
there are intervals on every page that hitherto no human
voice has been able to produce purely. If the composer had
not revealed himself in his true guise in the preface, we would
regard the entire collection as a satire of the most miserable
pieces that have appeared to date. In that case we wouldn’t
find anything wrong — for all of the errors of scansion,
declamation, melody, harmony, and rhythm look exactly as
if they had been placed next to one another with mischievous
intent — except perhaps that it would be going too far to try to
improve the satire by the completely false and nonsensical musical
orthography. For when young composers have not yet learned
to write everything correctly, they take care to have their
keyboard teacher check their work before they give it over to
the press. [...]

The 1789 “Christmann” article on Böcklin blames the errors on the copyist and the engraver, and implausibly summarizes Schubart’s critical review as follows:

[...]                                                                   Schubart
recensirte sie in seiner damaligen Chronik auf eine Art,
die sowohl dem Genie, als dem Geschmack ihres
Herrn Verfassers zu vorzüglicher Ehre gereichen
mußte. [...]
[Musikalische Real-Zeitung, no. 19, 13 May 1789, col. 152]

[...]                                                                     Schubart
reviewed [the collection] in his Chronik at the time in such
a way that it bestowed tremendous honor on the genius
as well as the taste of their composer. [...]

One begins to understand Gerber’s anger at being duped over the quality and reception of Böcklin’s music.

In his foundational study of the German lied, Max Friedlaender wrote of Böcklin’s XXIV Lieder:

[I]n der That erweisen sich die 24 Compositionen als die eines überaus schwächlichen Dilettanten, der weder eine Melodie zu erfinden noch den Text zu declamiren weiß. [...]

Böklin gehörte eben so wie Eschstruth zu den unbedeutenden aristokratischen Musikdilettanten, die ihrer äußeren Stellung wegen von Einfluß waren und leider auch unter den Fachmusikern gefällige Federn fanden durch die ihre Verdienste in außerordentlich übertriebener Weise gerühmt wurden. [Friedlaender 1903, 222]

In fact the 24 compositions prove to be those of an exceedingly weak aristocrat, who knows neither how to invent a melody nor how to declaim a text. [...]

Böcklin, just as with Eschstruth, belongs to the unimportant aristocratic musical dilettantes, who had influence on account of their outer appearance, and unfortunately found their contributions praised in an extraordinarily exaggerated manner by the accommodating pens of professional musicians.

Friedlaender attaches a footnote to this last sentence referring to the “Christmann” article on Böcklin in the Musikalische Real-Zeitung as an example of an “accommodating pen.”

The other works currently attributed to Böcklin in the RISM online catalog are:

• Lieder verschiedener Dichter, in Melodien zum Gesang und Klavier gesetzt
• VI Trios (guitar, flute, viola), op. 30
• Notturne (violin, guitar, viola), op. 34
• Amusement pour le beau monde (violin, 2 guitars, cello), op. 35
• "Das Grab" (song), in Anthologie für Kenner und LIebhaber der Tonkunst, vol. 2 (1789)
• "An die Liebe" (song, manuscript)

A scan of the VI Trios pour la Guittare avec Flute et Alto, op. 30, is available through BSB. The opus numbers 30, 34, and 35 suggest that there may have been earlier publications, but none are currently known.

The review of Böcklin’s Beyträge in the Musikalische Korrespondenz in 1790 includes a reference to Mozart in a sentence that can be seen as expressing the reviewer’s opinion rather than Böcklin’s, and it is thus itself a minor Mozart document (it is not in Dokumente or Neue Folge). In regard to Böcklin’s second letter, the reviewer writes:

[...]     Ueberall stößt man darinn auf einseitige
und schiefe Urtheile über Tonkünstler und ihre
Werke, die mit Digreßionen vermischt sind, die
gar nicht einmal zur Sache gehören, wie S. 26 f.
Gluk, Salieri, Mozart, Haydn und von Ditters=
dorf sind freilich Namen, die ihren Rang in der
Geschichte der Kunst verdienen. Aber wer seinen
Mann nicht so ins Gesicht fassen kann, wie Forkel
einen Gluk bei der Beurtheilung der Riedelschen
Briefe über demselben, der würde dem Publikum
immer noch einen größern Dienst leisten, wenn er
ihm nur eine trokene Biographie von solchen
Männern mittheilte. [...]
[Musikalische Korrespondenz, no. 8, 15 Aug 1790, cols. 59–60]

[...]    Everywhere [in the book] one runs into
one-sided and biased opinions about musicians
and their works, mixed with digressions that
have nothing to do with the topic, as on p. 26ff.
Gluck, Salieri, Mozart, Haydn, and von Dittersdorf
are indeed names that earn their place in the
history of the art. But whoever cannot look clearly
at his man, as Forkel does with Gluck in his
assessment of Riedel’s Briefe on the composer,
that person would do the public a greater service if
he gave only a dry biography of such men. [...]

(The references are to Friedrich Justus Riedel, Ueber die Musik des Ritters Christoph von Gluck, 1775, and Johann Nickolaus Forkel’s book-length review of Riedel’s book in the Musikalisch-kritische Bibliothek, vol. 1, 1778, 53–173.)

It is worth noting that the review of Böcklin’s Beyträge in the Allgemeine Literatur-Zeitung 1792, criticizes the book for giving Mozart and Salieri short shrift relative to (in the author’s opinion) nonentities like Schubart.

Böcklin is in many respects a sad figure: a minor aristocrat who was the product of a broken home, whose own marriage was unhappy and finally failed, burdened with his father’s debts for much of his life, with intellectual and artistic ambitions that his talent and education were insufficient to meet. Historical diagnosis is always perilous (and impossible to verify), but the references to Böcklin’s melancholy, combined with his grandiloquence and inflated representation of his own musical merit, as well as an apparent family history of volatile personalities, could be taken to suggest bipolar disorder. That Böcklin was vain there can be little doubt: he seems to have clung fiercely to his mostly meaningless titles and memberships. On the title page of his Vom Ursprung, Vorzügen und Hindernissen des Getreidebaues (1786), at a time when many authors of his class published anonymously, Böcklin identifies himself as:

He was also a name-dropper, claiming to have studied with Schobert, Jommelli, and Richter, and to have been friends with Gluck, Vogler, and Sacchini.