Seventeen ninety-one was a very good year for Mozart. It was also a very bad year. It was good because, being at the height of his creative powers, he composed an amazing series of masterpieces, including The Magic Flute. It was a bad year because he was in poor health, out of favor with the aristocratic establishment that had been his main support for decades, and he was in financial difficulty (a related factor). Worst of all, at the end of the year, he died.

In addition to The Magic Flute, the list of 1791 masterpieces includes (but is not limited to) such remarkable works as the opera La clemenza di Tito, the Piano Concerto No. 27 in B-flat (arguably his greatest), the supreme Clarinet Concerto, the great String Quintet in E-flat, the motet Ave verum corpus, the Requiem, and two works for glass harmonica that are not well known to the musical public but are among his most haunting music: the Adagio, K. 617a, and Adagio and Rondo, K. 617.

This flood of masterpieces is all the more remarkable because Mozart was coming out of one of his bleakest years. Seventeen ninety was the least productive year of his adult life and it was a year filled with pathetic pleadings to his friend Michael Puchberg for loans. To Puchberg's eternal credit, he always responded, though not always in the amounts Mozart wanted.

It was Mozart's misfortune to live in a time of great change. European aristocracy was in decline. The American Revolution had alarmed the governing class of Europe to an extent that Americans today do not grasp. Even more ominously, the French Revolution was under way, though the Terror was still to come. For the aristocrats, there were plenty of dangers elsewhere. Some were real, others the fearful imaginings of uneasy rulers.

Expanding to fill the growing vacuum at the top was the upper middle class, in which merit counted for more than genealogy. What this meant for creative and performing musicians (Mozart was both) was a switch from a system of secure salaried positions to the riskier life of a freelance artist.

Some were able to make the transition smoothly. An example is Haydn, who spent most of his adult life as an employee of a prince, but after his retirement (with a pension roughly equivalent in value to a Social Security pension today) was able to do quite well on the musical free market. A few years after Mozart, Beethoven was able to exist purely as a freelance musician, though not without financial worries.

We'll never know how Mozart would have made the transition, because he died before the point could be established. But The Magic Flute (and most of the other compositions of 1791) shows that he could have earned a living, though hardly great riches.

This brings us to an interesting subject: How much did Mozart make for The Magic Flute? Those who think that putting a price tag on a great work of art is a vulgar exercise should be aware that all three of the greatest Viennese classical composers, Haydn, Mozart, and Beethoven, were keenly interested in the subject.

It's not easy to establish the monetary value of historical works for several reasons. In the first place, we may not know the original figure. In the second place, numbers alone are meaningless; we have to establish buying power. Finally, establishing historical exchange rates and bringing them up to date (in the case of The Magic Flute, over a period of 215 years) is a difficult task. Still, with the help of that remarkable modern tool, the Internet, it is possible to come up with figures that, even if arguable, are based on known facts.

No record exists of the fee that Mozart charged for The Magic Flute. However, we do know the fee he earned for two other operas of about the same time, Cosí fan tutte and La clemenza di Tito. For each, it was 900 Austrian gulden or florins (the terms were used interchangeably). In addition, he received 225 gulden in expense money for Tito to cover travel from Vienna to Prague for the rehearsals and premiere.

The Magic Flute was written for a friend and theatrical entrepreneur, Emanuel Schikaneder. He was quite successful, so it is reasonable to assume that Mozart earned what seems to have been his standard fee for an opera, 900 gulden.

The British pound served the same function in international finance in the 18th century that the American dollar does today. Sources disagree slightly as to the historical exchange rate. The American scholar H.C. Robbins Landon, in Mozart's Last Year (1988), writes that 24,000 gulden equaled £2,400 in Mozart's day, or an exchange rate of 10 Austrian gulden to a British pound. The German scholar Volkmar Braunbehrens, writing in Mozart in Vienna 1781-1791 (1989), puts 2,400 florins at £300 in 1790, or a rate of eight gulden to the pound. Splitting the difference, we can assume a rate of nine gulden to the pound.

Turning to the Web site www.eh.net/hmit, a good source for the value of old money, we find that 1791's 900 Austrian gulden would have been worth £7,368 in Britain in 2002 (the latest year for which the site's calculator works). Translating this into American dollars, and taking into account inflation from 2002 to 2005, we can finally propose that Mozart earned the equivalent of $14,139 for The Magic Flute. Or about the price of a low-end subcompact car.

If we stay strictly with 18th-century figures, we get an idea of Mozart's earnings that no one can argue with. For instance, the rent that Mozart paid for the apartment where he and his wife lived while he wrote The Marriage of Figaro was 450 gulden a year. So The Magic Flute would have paid two years' rent. The opera would have earned more than enough to pay for two years' schooling for Mozart's son Karl; the school where Mozart wanted to send Karl charged 400 gulden a year for board and tuition.

An interesting account of everyday life in Mozart's city is Sketch of Vienna by Johann Pezzl, an exact contemporary of the composer. Major portions of Pezzl's lengthy work are reprinted in English in Robbins Landon's Mozart and Vienna (1991). Pezzl calculated that a single man could live a "fairly comfortable" middle-class life on an income of 500 to 550 gulden per year, though he would have to be careful about his expenses.

Of course Mozart, who had a wife and two children and the need to keep up appearances because he moved in aristocratic circles, would have needed considerably more.

Incidentally, in 18th-century Europe, as in America today, it was more profitable to be a prominent concert pianist than a composer. In a 1785 letter, Mozart's father wrote that his son made 559 gulden from a single concert he gave. For his six quartets dedicated to Haydn, which were published in the same year, his publisher paid him a fee of 450 gulden (there were no copyright laws, so there were no subsequent royalties).

If it was profitable to be a concert pianist, it was even more profitable to be an aristocrat. Archbishop Colloredo of Salzburg, Mozart's old boss and a man whom he despised, was granted an annual pension of 80,000 gulden after he abdicated in disgrace. He had to keep up appearances, too.

But enough about fees and expenses. The Magic Flute's actual worth is beyond calculation. A hit with the public at the beginning, it has never been out of the operatic repertory. People still laugh at jokes written in 1791 and the beauty of Mozart's music has never aged.

The circumstances of the creation of The Magic Flute are a good example of the social transformation under way in Mozart's day. La clemenza di Tito, written at the same time, was the result of a royal commission. Schikaneder was no aristocrat, and his theater, where The Magic Flute premiered on September 30, was a low-brow venue. Braunbehrens describes it as a place for "cabaret, farce, revue, and clown show that utilized every possible comic form and theatrical cliché." Still, "it was always relevant to the times and never lost sight of the Enlightenment maxim that theater should edify as well as entertain."

The Magic Flute combines these opposing elements beautifully. Sarastro, Tamino, and Pamina exist on a higher intellectual and moral plane. Papageno and Papagena (who have more fun) provide comic relief. Where did Mozart stand? It is clear from his letters and the accounts of his contemporaries that there was something of both elements in his personality. In The Magic Flute he created a work of art that transcended barriers of class and time.

Olin Chism writes for the Dallas Morning News.