How Do We Come to Know So Much about Mozart?
One of the reasons we find Mozart so fascinating is that we are fortunate to know so many details of his life. For example we know quite accurate itineraries of his travels: where he went, how he traveled, when he arrived, how long he stayed. When we add it all up, it comes to more than 3,700 days - an almost incredible total of more than ten years out of a lifetime of only 35 years!

We also know what he thought about many other composers, what some of them thought about him, what he thought about many musicians and singers of his time, about some of the royals and nobles he dealt with, and about some of his students. About many of his compositions we know why he wrote them, when, and for whom. We know a lot about his relationships with his immediate family.

He was, of course, a prolific composer, having written more than six hundred works that we know about. He was also a prolific letter writer, and fortnately many of the letters were saved that he wrote to his Mama, his Papa, his sister Nanerl, his cousin Maria Anna Thekla Mozart, his wife Constanza, and others. Those letters are a gold mine of insight, and give us a wonderfully intimate view into Wolfgang's real life.

The following few letters are a brief sample quoted from the many dozens in the excellent book
Mozart's Letters
Mozart's Life
by Robert Spaethling, which is a great source if you'd like to see translations that really convey the spirit of many more of Mozart's letters. The original letters are written mostly in German, although Mozart also knew and used Italian, French, and English, among others; Spaethling brings them to life for English language readers.

This is Mozart's first known letter, written to his mother at the age of 13.

To his mother Anna Maria Mozart in Salzburg (postscript)
Wörgl, December 14, 1769
My dearest mama,
My heart is filled with alott of joy because I feel so jolly on this trip, because it's so cozy in our carriage, and because of coatchmannn is such a fine fellow who drives as fast as he can when the road lets him. Papa has propably already given to mama the news of our trip, the reason I am writing to mama is to show that I know my duty, so I remein in deepest Respekt her devoted son.
Wolfgang Mozart

Wolfgang certainly did have a silly side, as we can clearly see in this letter written at the age of 21 to his favorite cousin.

To his cousin Maria Anna Thekla Mozart in Augsburg
Manheim, November 5, 1777
Dearest cozz buzz!
I'm asking you, why not? - I'm asking you, dearest numbskull, why not? - if you are writing anyway to Madame Tavernier in Munich, please include regards from me to the Mademoiselles Freysinger, why not? - Curious! Why not? - and to the Younger, I mean Frauline Josepha, tell her I'll send my sincere apologies, why not? - why should I not apologize? - Curious! - I don't know why not? - I want to apologize that I have not yet sent her the sonata that I promised, but I will send it as soon as possible, why not? - what - why not? - why shouldn't I send it? - why should I not transmit it? - why not? Curious! I wouldn't know why not? - well, then you'll do me this favor; - why not? Why shouldn't you do it for me? Why not, it's so strange! After all, I'll do it for you, too, if you want me to, why not? - why shouldn't I do it for you? - curious! Why not? - I wouldn't know why not?
And now I must close and that makes me morose....Now farewell, I kiss you 10000 times and I remain as always your
Old young Sauschwanz,
Wolfgang Amadé Rosenkranz

To his father Leopold Mozart in Salzburg
Vienna, at the Prater, May 3, 1783
Mon trés cher Pére!
I just can't make up my mind to go back to the city so early - the weather is so beautiful - and it's so pleasant to be in the Prater today. - We had a little something to eat here in the park, and now we'll stay until 8 or nine o'clock in the evening. - The only company I have is my pregnant little wife - and her only company - consists of her little husband, who isn't pregnant but fat and happy. - … I just didn't want to miss out on this beautiful weather, especially for the sake of my dear wife - after all, a little walking is good for her. - I only wanted to tell you today that we are both well, God be praised, and we received your last letter all right. - Farewell.
We kiss your hands 1000 times and embrace our dear sister with all our heart and are Forever your
obedient children
W. A. and C. Mozart

Mozart worked long and hard on a set of six string quartets, which he dedicated to Franz Josef Haydn. Wolfgang said that was only proper, as it was Haydn who had taught him to write a string quartet. Papa Leopold was in Vienna as Haydn and Mozart played through those quartets together for the first time, and Haydn said to Papa Leopold, "Before G-d and as an honest man, your son is the greatest composer known to me, either in person or by reputation." Here is that dedication.

To Franz Josef Haydn
Vienna, September 1, 1785
To my dear friend Haydn,
A father, having decided to send his children out into the wide world, felt that he should entrust them to the protection and guidance of a famous Man who by good fortune also was his best Friend. - Here they are, distinguished Man and dearest Friend, my six children. - They are, to be truthful, the fruit of long and laborious efforts; however, the hope given me by various Friends that my efforts will be at least somewhat rewarded encourages and flatters me to think that this offspring will be of comfort to me someday. You yourself, dearest friend, told me of your approbation of them during your last Visit here in our Capital. This acceptance gives me the courage to commend them to you and makes me hope that they would not be completely unworthy of your favor. May it please you to welcome them kindly and to be for them a Father, Guide, and Friend! From this moment on I hand over to you all my rights in them, begging you, however, to consider with indulgence their flaws, which a Father's uncritical eye may have overlooked, and in spite of them continue your generous Friendship toward one who so greatly appreciates it, while I remain, Dearest Friend, with all my heart, your most Sincere Friend,
W. A. Mozart

To Michael Puchberg in Vienna
Vienna, early June, 1790
Dearest Friend and Brother of the Order,
I am in town to conduct my opera. My wife is feeling a little better - her pains have begun to subside a bit; but she'll have to take 60 baths; - so she'll have to make another pilgrimage out there later in the year; - my God grant that it will help. - Dearest friend, if you could help me with my most urgent expenses, please do it; - to save money I'm staying here with her in Baden and come into town only when it is absolutely necessary. - I am forced to sell my quartets, all that hard work, for a trifle, just to get some cash into my hands and meet my immediate obligations. - I have also begun to compose some Clavier sonatas with that in mind. - Adieu - send me whatever you can spare. - One of my masses will be performed at Baden tomorrow. Adjeu - it's about 10 o'clock. Forever yours,
P.S. Would you kindly send along my viola.

To his wife Constanza in Baden
Vienna, October 8, 1791
Dearest and most beloved little wife! -
With the greatest delight and joy I found your letter waiting for me when I returned from the opera; - the opera was performed again to a full house with the usual applause and repetition of numbers, even though Saturday is always a bad day for opera because it is postal day; -
I have just consumed a delicious piece of sturgeon, which Don Primus, that faithful servant, served me - and since I am having a rather healthy appetite today, I sent him off to bring me, if possible, another slice. - In the meantime I shall continue with my letter to you. -
When Papageno's aria with the Glockenspiel came on, at that moment I went backstage because today I had a kind of urge to play the Glockenspiel myself. - So I played this joke: just when Schikaneder came to a pause, I played an arpeggio - he was startled - looked into the scenery and saw me - the 2nd time he came to that spot, I didn't play - and this time he stopped as well and didn't go on singing - I guessed what he was thinking and played another chord - at that he gave his Glockenspiel a slap and shouted, "Shut up!" - everybody laughed. - I think through this joke many in the audience became aware for the first time that Papageno doesn't play the Glockenspiel himself. - By the way, you can't imagine how charming the music sounds when you hear it from a box close to the orchestra. - As soon as you come back, you'll have to try it out. - I am coming out to Baden next Sunday for sure - and on Monday we'll come home together. - Farewell, my dear! - I kiss you a Million times and am Forever your