[Nettl was a distinguished musicologist. In the essay below, he examines the influence of Casanova upon Da Ponte and upon the writing of Don Giovanni.]

Of all the great figures of the eighteenth century, there is probably none that we more instinctively associate with the hero of Mozart's opera Don Giovanni than Giacomo Casanova. It is, indeed, one of the most curious coincidences in the history of art that this man, who was the incarnation of Don Juan in real life, should not only have been alive, but even have been in Prague when Don Giovanni was first produced in 1787. To find an appropriate parallel we almost have to imagine Hamlet rising out of his grave to be on hand for the first presentation of Shakespeare's great tragedy in London. Yet the extraordinary connection between Casanova and Don Giovanni is one which no historian of music has yet investigated seriously.

I still vividly recall the thrill I experienced years ago (1924) on discovering just how unusual this connection was. It was while I was searching through the Casanova papers that are stored near the little Bohemian town of Dux (northwest of Prague), in the castle of which the great Italian adventurer spent his last thirteen years as the librarian of Count Waldstein. At the time I visited Dux his papers were watched over by a vivacious little man called Bernard Marr, who, besides being a machine manufacturer, was a fanatical cabalist and admirer of Casanova, and had given such noted writers as Arthur Schnitzler, Stefan Zweig, and Max Brod invaluable information. Among the handwritten manuscripts that Marr showed me were two of quite exceptional interest. On examining them closely I realized that they were nothing less than a revision of part of the libretto of Don Giovanni. It was apparent that Casanova had managed to study the libretto in detail, and that he had set out to revise some of it, or even to rewrite it entirely for Mozart or some other composer. This posed a fascinating riddle—just how had Casanova succeeded in getting hold of the text, and why had he done so?

The Casanova archives, which are now stored at Hirschberg, near Dux, are full of letters from Da Ponte, who bombarded the old Chevalier with accounts of his travels and with requests for aid and advice right up to the year of Casanova's death in 1798. There was even a time, in 1792, when Da Ponte, who was then in London and very much down on his luck, tried to get Casanova to procure him a sinecure from his own patron, Count Waldstein; a request which Casanova answered with characteristic cynicism by advising Da Ponte to live off his newly married wife's income. Furthermore, Da Ponte's memoirs, which he wrote in New York (after an unusual career as a grocer, distiller, language teacher, professor at Columbia, boarding-house owner, and impresario) contain a number of references to his old friend Casanova, whom he obviously considered one of the most remarkable men he had ever met.

To appreciate the extent of this influence it is necessary to know something of the background of the two men. Both were originally Venetians and began by leading somewhat parallel lives. Both belonged to that class of Italian adventurers who lived off their native wits and who could be found in the eighteenth century in all the royal courts and noble circles of the great European capitals. At one moment they would be living the life of cavaliers, driving about in four-horse carriages, throwing lavish parties, and moving in the company of beautiful women, only to find themselves in the next without a penny and forced to borrow from some old friend the money with which to pay for the previous night's lodgings. But with all this there was one important difference: Casanova was born in 1725 and was twenty-four years senior to Da Ponte, who was born in 1749, so that it was natural that the first should be a model for the second, rather than a contemporary rival.

In his memoirs Da Ponte tells us that he first met Casanova in 1777 in the palaces of the Venetian noblemen, Memmo and Zaguri, both of whom were patrons of the arts. At the time that Casanova and Da Ponte were living there Venice was at its most bewitching, and both revelled in the frenzy of its masked carnivals and nocturnal festivities. Like Casanova, the young, Lorenzo da Ponte had originally been destined to become an abbé in the Church, but he was soon expelled from the seminary he was teaching at for having written some public verses inspired by Rousseau. Even before his expulsion, however, his morals had run aground on the tempting reef of Venice's loose, glittering life, and his vow of chastity and celibacy had not restrained him from indulging in numerous love affairs and seductions. Once freed of his sacerdotal bonds he gave free rein to his amorous inclinations, and it was here, in a Venice where Casanova was Don Giovanni in the flesh, that Da Ponte imbibed that rich, erotic atmosphere which he later depicted with such mastery in Mozart's opera.

While Da Ponte's adventures in Venice were not as sensational as Casanova's, they were basically not so different. It was not long, indeed, before the gay city grew too hot for both of them. Thanks to the account of it he gives in his memoirs, Casanova's story of his imprisonment in the Doge's Palace and his escape over its leaden roofs has become world-famous. What occasioned it was his arrest by the Venetian Tribunal for spreading a tale about an affair between a nun and the French Ambassador (who later became Cardinal Bernis). Da Ponte's departure from Venice was not as dramatic, but he too was arraigned for trial and had to flee the city.

After passing some time in various European cities Casanova and Da Ponte met again in Vienna. In his reminiscences Da Ponte says that Casanova stayed several years in the Austrian capital, "though neither I nor anyone else knew what he was doing there, or what he was living on; I conversed with him frequently, and on every occasion he found my house and purse open to him. Although I could approve neither of his principles nor of his way of life, I nonetheless paid great heed to his counsels and precepts which truly—I perceive it now—were of the highest value, golden rules which I unhappily too little followed and from which I could have drawn the greatest advantage had I but put them into practice. . . . "

The importance which Da Ponte here attaches to Casanova and to his advice is an eloquent tribute to the older Italian's influence over the younger. But the friendship which ripened between them in Vienna is of special interest for another reason which has a direct bearing on the later composition of Don Giovanni. In his memoirs Da Ponte relates how one day, while he was strolling along a street in Vienna with Casanova "I saw him suddenly knit his brows, gnash his teeth, and begin to turn and twist, and uttering a yell and throwing up his hands to Heaven, rush away from me and hurl himself furiously upon a man he appeared to know, shouting at the top of his voice, 'Assassin, now I have caught you!'" The "assassin" turned out to be a former servant of Casanova's called Costa, who for many years had been his companion and friend. But one day in France, immediately after Casanova had cheated an aging Marquise out of a small fortune in gold and jewels by administering a dose of laudanum in place of the magic elixir of life that he had enthusiastically promised her, this servant had decamped with the booty and not been seen again. Following the uproar in the street caused by Casanova's assault on him, Costa, who had now become the valet of a Viennese nobleman and something of a "poet" on the side, disappeared into a coffee-house and sent Casanova a poem of six lines:

Casanova, make no fuss
You stole and I did too.
You were the master, I the pupil
I learned your trade too.
It was only tit for tat,

This incident is significant not only because it shows us another facet of Casanova's many-sided and versatile personality, but also because Da Ponte witnessed it personally. For this same Costa, the servant who had learned his master's tricks so well that he could one day use them against him, was destined to be the living model for Don Giovanni's servant, Leporello (rather different than Signarelle of Moliere's Don Juan).

The choice of Don Juan as the subject for a new, opera in Prague was Da Ponte's—so at least he tells us in his memoirs. Mozart, at any rate, was enchanted with the idea from the start. The theme, as it happened, was very much in the air. Though the Italian poet Goldoni had tried to make fun of the Don Juan legend some fifty years before by writing a dramatic extravaganza called Don Giovanni Tenorio o sia Il Dissoluto, the story of the dissolute hero from Seville had remained a popular one with the Italian stage. In fact, in the very year that Mozart and Da Ponte received their new commission, the Italian librettist Bertati and the composer Gazzaniga had written an opera on the Don Juan theme entitled Il Convitato di Pietra. First put on for the Venice carnival in February 1787 it had been an instantaneous "hit" and had conquered all of Italy in months, even though Goethe, who saw it during his trip to that country, thought it ridiculous.

Da Ponte may have been of the same opinion, for he set out to do better. He even undertook to write three operas at once, and with typical verve he told Emperor Joseph II: "I shall write at night for Mozart as though I were reading Dante's Inferno; I shall write in the morning for Martini, and that will be like studying Petrarch. The evening will be for Salieri, and that will be my Tasso." The Emperor seems to have been amused by this scheme, though he doubted that Da Ponte could carry it out. In fact, of course, and notwithstanding Da Ponte's verbal flourishes, The Divine Comedy was only a minor source of inspiration to him in writing the text for Don Giovanni. To get in the right mood he set a bottle of Tokay on the right side of his desk and a Sevilla snuffbox on the left, and set out to work twelve hours a day, stopping every now and then to revive his poetic inspiration by carrying on an affair with the sixteen-year-old daughter of his housekeeper. He also helped himself liberally to whole chunks of Bertati's script, including the famous "Catalogue aria," in which Don Giovanni's servant lists his master's numberless seductions. But as he did so the vision of his old friend, Casanova, and his servant, Costa, might have hovered before his eyes and have inspired him to transform Bertati's pallid figures into the lusty, flesh-and-blood Don Giovanni and Leporello which, thanks to Mozart's music, have become for opera what Don Quixote and Sancho Panza are for literature.

After completing the text in Vienna Da Ponte arrived in Prague early in October to oversee the final preparations. He remained mere a few days and was present at a number of rehearsals held at the National Theatre. But before the opera could be produced he was forced to return suddenly to Vienna. Mozart was thus left without an Italian librettist capable of making last-minute adjustments in the poetic text to suit the whims or the complaints of the singers. It is at this point that the mystery surrounding Casanova's involvement in me preparations of Don Giovanni begins.

The memorable premiere of Don Giovanni took place on October 29. There can be no doubt that Casanova was in Prague at the time, for on November 4 Count Lamberg wrote from Brunn to the Bohemian writer J. F. Opitz at Caslau that "Casanova is in Prague; his letter to me is of the 25th of October." He was in fact at that moment negotiating with his publisher, Schonfeld, about me publication of his novel Icosameron. He was also almost certainly in touch with Mozart. The subscription list to Icosameron (contained in me back of the first edition) includes a number of names mat we encounter in Mozart's life—to mention but one: that of Count Pachta, for whom Mozart wrote me German Dances while in Prague.

None of the available scraps of evidence offer any conclusive proof that Mozart and Casanova met at this time. However, in his book Rococcobilder (Scenes from the Rococco), which was published in 1871, the poet and historian Alfred Meissner claims mat they did in fact meet at a party given by the singer Josephine Duschek (a friend of Mozart's) in her villa near Prague. The occasion was one of those famous "evenings" at the Duschek villa. Both Da Ponte and Casanova, Meissner says, were among the guests. All those present were disturbed by the unconcern of Mozart, who had still not finished the overture to Don Giovanni, though the dress rehearsal was due the next day and the first performance the day after.

The most important clue in this mystery is constituted by the two manuscript sheets which Bernard Marr and I discovered years ago in Dux. These two sheets represent a revision of the sextet that is sung in the second act of Don Giovanni when Donna Anna, Donna Elvira, Don Ottavio, Zerlina, and Masetto discover Leporello in the disguise of Don Giovanni, whom he has faithfully been trying to imitate by seducing Donna Elvira. In the second half of this scene, as Da Ponte wrote it, there is a bit of unaccompanied recetative in which Zerlina, Elvira, Ottavio, and Masetto threaten to punish Leporello, and this is followed by a G major aria beginning "Ah, pietà, Signori miel!" in which Leporello attempts to exonerate himself on the grounds that Don Giovanni had forced him to disguise himself.

The two Casanova fragments, which contain about thirty lines each, were both evidently written for formal musical accompaniment. Neither is numbered and each ends with the stage direction fugge (he escapes), which seems to indicate that they were written as alternative versions for the last part of the scene. They overlap with Da Ponte's text in that the first is a quintet, evidently intended to replace Da Ponte's recitative, and the second is an aria for Leporello.

In a second edition of his book Mozart's Operas (published after our discovery of the fragments) Professor Edward Dent has advanced the theory that at some moment during the rehearsals in Prague several of the singers may have complained about the lack of solo arias allotted to them, and that to satisfy them Mozart decided to introduce a scene after the sextet for Ponziana, who was singing the role of Leporello, and Baglioni, who had that of Ottavio. He therefore got Casanova, in Da Ponte's absence, to write the words for it. "Casanova," says Dent, "first sketches the aria for Leporello . . ., followed by an ensemble for all the characters except Donna Anna, who has left the stage at the end of the sextet. Mozart then probably points out that the audience already knows everything that Leporello says in this aria, and that another ensemble would be an anti-climax. Casanova rewrites the scene under Mozart's direction, making it much less formal and far more amusing and dramatic. As Mozart has taken away the sheet with the revised words, it is naturally lost; Casanova puts the rejected draft in his own pocket, and accident has preserved it. This reconstruction of what may have happened is purely conjectural."

Though conjectural, it is an ingenious theory. It does not tell us, of course, if the revised sheet that Mozart took away with him and which has been lost was ever used, or how it was fitted into the Da Ponte libretto as we know it, unless we are to suppose that Leporello's G major aria was the result of this revision, that is to say, that it was really written by Casanova and inserted into the final text. That is an entertaining notion to play with, but it seems highly unlikely that such a thing could have happened.

The libretto for Don Giovanni was definitely printed before Da Ponte left Prague. Furthermore, it had to be approved by the censor prior to the first performance. For this reason I doubt that any text of Casanova's, supposing that he wrote one for Mozart, was used at the premiere.

My own theory—and like Professor Dent's it is only a conjecture—is that Mozart may have asked Casanova to write a couple of additions to Da Ponte's text after the highly successful premiere, in order to satisfy the singers and particularly Ponziani (Leporello), who was the only singer in the opera who did not have two solo arias. (Lolli sang both the roles of Masétto and the Commendatore.) These additions may have taken the form of "prepared" improvisations, somewhat equivalent to what is known today as "encores." According to Luigi Bassi, who sang the first Don Giovanni, the opera director of Prague, Guardasoni, allowed quite a bit of such "impromptu" singing. It even seems that Mozart attached considerable importance to it, particularly in the dinner scene. Such improvisations were standard practice in Prague right up until fairly recent times, and I still recall old-timers of the Prague Opera House telling me years ago of how Don Giovanni always used to end with a chorus ensemble, culminating in "Evviva il immortale Maestro Mozart."

Regardless of what theory is advanced to explain the Casanova text, it differs significantly from Da Ponte's in both words and spirit. Casanova's is not only more formal and elaborate, as would be natural for words destined for a full musical accompaniment; it is more flamboyant in every way. Where, for example, Da Ponte has Zerlina, Elvira, Ottavio, and Masetto arguing as to who is to be the one to punish Leporello as he deserves, Casanova has them list all the dreadful fates that are about to overtake the hapless servant:

Zerlina: Ti vo mangiar le viscere (I am going to eat your entrails).

Masetto: Vo divorarti l'anima (I am going to devour your soul).

Don Ottavio: Appreso ad unpatibolo (I'll bring you near a chopping block).

Donna Elvira: Pericolor lo spirito (To scare the wits out of you).

Having thus emphasized the distinction between the rather grotesque chastisements envisaged by plebeians and the more sophisticated punishments of aristocrats, Casanova has all four join with Leporello in a lively quintet:

All four: Alla forca, alla forca, alla forca (To the gallows, etc.).

Leporello: Ohibo, che morte sporcai (Alas, what a dog's death!).

All four: In galera, in galera, in galera! (To the galley, etc.).

Leporello: Remo, bussa, vita austera! (Rowing, steering, austere life).

All four: Vada a scopar la piazza (Go sweep the square).

Leporello: Sono di illustre razza (I am of illustrious family).

In this last line Casanova has carried Leporello's effrontery in imitating his master to heroic heights—and we can only admire this lovely touch from the old boudoir buccaneer who had conferred on himself the high-flown title of Chevalier de Seingalt!

The same personal flavor can be found in Leporello's aria, as Casanova wrote it, in comparison with Da Ponte's. Whereas Da Ponte's presents a rather breathless Leporello trying to explain away his disguise and his presence in the courtyard of Donna Elvira's house, Casanova's Leporello appears much less intimidated, and even capable of philosophical reflections:

La colpa e tutta quanta (The fault is all alone).

Di quel femíneo sesso (Of that feminine sex).

Che l'anima gl'incanta (Which enchants the soul).

E gl'incantera il cor (And will enchant the heart).

O sesso seductor! (O seductive sex!).

Sorgente di dolor! (Source of sorrow!).

And he ends up on a really sublime note of insolence, crying:

Il solo Don Giovanni (Don Giovanni alone).

Merita vostro sdegno (Merits your indignation).

Iro a punir l'indegno (I'll go punish the scoundrel).

Lasciatemi scappar . . . (fugge) (Let me but escape [he flees]).

The whole "tone" of the two versions of the last part of the sextet is, in fact, quite different. Whereas Da Ponte's is graceful, reserved, urbane, and obviously written for a courtly audience, Casanova's text is uninhibited, exuberant, and at times almost improper. The contrast is the same that we find in their respective memoirs, the same that we find in their respective lives: the difference between two types of man—the one, Da Ponte, an accommodating man of letters, prepared on occasion to be a hypocrite and to draw a cloak of modesty over his more dubious escapades, the other: Casanova, a flamboyant exhibitionist, every ready to startle his listeners with some scandalous and unbelievably lascivious tale.

The Danish philosopher, Soren Kierkegaard, considered it a stroke of fortune that it should have fallen to a composer of Mozart's genius to exploit the unique material of the Don Juan theme, just as it fell to Homer to mould the stuff of the Trojan Wars into epic verse. For Kierkegaard, Mozart was the master of the erotic in music, and to prove his point he cites the amorous intoxication of Cherubino and the earthy simplicity of Papageno. To these we could add the coarse sensuality of Monastatos. It is in Don Giovanni that the "erotic age" finds its glorification, just as it is in Casanova's memoirs that it finds its definitive documentation. Not that the lasciviousness of Casanova's adventures can be lumped together in the same pot with Mozart's heavenly melodies; but both share a common ground and breathe the same air. The difference is that whereas with Casanova the spiritual is sensualized, with Mozart the sensual is made sublime.